I have deployed a simple sitecore website in azure paas. there's nothing so special about the code as it is only a newsletter sign up with personalization. It works well, I can personalized my vistors, trigger a goal and view it in the sitecore backend trhough experience profile and analytics. Everything is working smoothly as i expected. Until .. I opened my Experience Editor which throws the error below in the ribbon section. 

    Server Error in '/' Application.
    siteName
    Description: An unhandled exception occurred. 
    
    Exception Details: System.InvalidOperationException: siteName
    
    Source Error: 
    
    
    Line 2:  @using Sitecore.ExperienceEditor.Speak.Ribbon.Controls.QuickbarButton
    Line 3:  @model Sitecore.Mvc.Presentation.RenderingModel
    Line 4:  @Html.Sitecore().Controls().QuickbarButton(Model.Rendering)
    
    Source File: d:\home\site\wwwroot\sitecore\shell\client\Sitecore\Speak\Ribbon\Controls\QuickbarButton\QuickbarButton.cshtml    Line: 4 
    
    Stack Trace: 
    
    
    [InvalidOperationException: siteName]
       Sitecore.Web.WebUtil.GetCookieValue(String siteName, String key, String defaultValue) +155
       Sitecore.ExperienceEditor.Speak.Server.Contexts.ItemContext.get_WebEditMode() +73
       Sitecore.ExperienceEditor.Speak.Ribbon.Requests.AddRendering.CanAddRendering.GetControlState() +87
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.RibbonButtonBase.ExecuteProcessComponentState(Object requestObject, T context) +247
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.RibbonButtonBase.GetProcessComponentState() +312
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.RibbonButtonBase.PreRender() +230
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.RibbonIconButtonBase.PreRender() +24
       Sitecore.Web.UI.Controls.ComponentBase.Render() +37
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.QuickbarButton.ControlsExtension.QuickbarButton(Controls controls, Rendering rendering) +126
       ASP._Page_sitecore_shell_client_Sitecore_Speak_Ribbon_Controls_QuickbarButton_QuickbarButton_cshtml.Execute() in d:\home\site\wwwroot\sitecore\shell\client\Sitecore\Speak\Ribbon\Controls\QuickbarButton\QuickbarButton.cshtml:4
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +252
       System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +148
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +122
       System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +136
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +257
    
    [InvalidOperationException: Error while rendering view: '/sitecore/shell/client/Sitecore/Speak/Ribbon/Controls/QuickbarButton/QuickbarButton.cshtml' (model: 'Sitecore.Mvc.Presentation.RenderingModel, Sitecore.Mvc').
    ]
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +729
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Render(Renderer renderer, TextWriter writer, RenderRenderingArgs args) +147
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Process(RenderRenderingArgs args) +73
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Extensions.EnumerableExtensions.Each(IEnumerable`1 source, Action`1 action) +190
       Sitecore.Web.UI.Controls.Common.ItemRenderers.ItemRenderer.RenderItem(TextWriter output, Item item) +270
       Sitecore.Web.UI.Controls.Common.ItemRenderers.ItemRenderer.Render(HtmlTextWriter output) +143
       Sitecore.Web.UI.Controls.ComponentBase.Render() +126
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.QuickBar.QuickBar.DoRender(HtmlTextWriter output) +233
       Sitecore.Web.UI.Controls.ComponentBase.Render() +126
       Sitecore.ExperienceEditor.Speak.Ribbon.Controls.QuickBar.ControlsExtension.QuickBar(Controls controls, Rendering rendering) +126
       ASP._Page_sitecore_shell_client_Sitecore_Speak_Ribbon_Controls_QuickBar_QuickBar_cshtml.Execute() in d:\home\site\wwwroot\sitecore\shell\client\Sitecore\Speak\Ribbon\Controls\QuickBar\QuickBar.cshtml:4
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +252
       System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +148
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +122
       System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +136
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +257
    
    [InvalidOperationException: Error while rendering view: '/sitecore/shell/client/Sitecore/Speak/Ribbon/Controls/QuickBar/QuickBar.cshtml' (model: 'Sitecore.Mvc.Presentation.RenderingModel, Sitecore.Mvc').
    ]
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +729
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Render(Renderer renderer, TextWriter writer, RenderRenderingArgs args) +147
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Process(RenderRenderingArgs args) +73
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Pipelines.Response.RenderPlaceholder.PerformRendering.Render(String placeholderName, TextWriter writer, RenderPlaceholderArgs args) +183
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Helpers.SitecoreHelper.Placeholder(String placeholderName) +258
       Sitecore.ExperienceEditor.Speak.PageEditbar.PageEditBar.Render(HtmlTextWriter output) +231
       Sitecore.Web.UI.Controls.ComponentBase.Render() +126
       Sitecore.ExperienceEditor.Speak.PageEditbar.ControlsExtension.PageEditBar(Controls controls, Rendering rendering, HtmlHelper`1 htmlHelper) +133
       ASP._Page_sitecore_shell_client_Sitecore_ExperienceEditor_PageEditbar_PageEditBar_cshtml.Execute() in d:\home\site\wwwroot\sitecore\shell\client\Sitecore\ExperienceEditor\PageEditbar\PageEditBar.cshtml:4
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +252
       System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +148
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +122
       System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +136
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +257
    
    [InvalidOperationException: Error while rendering view: '/sitecore/shell/client/Sitecore/ExperienceEditor/PageEditbar/PageEditBar.cshtml' (model: 'Sitecore.Mvc.Presentation.RenderingModel, Sitecore.Mvc').
    ]
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +729
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Render(Renderer renderer, TextWriter writer, RenderRenderingArgs args) +147
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Process(RenderRenderingArgs args) +73
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Pipelines.Response.RenderPlaceholder.PerformRendering.Render(String placeholderName, TextWriter writer, RenderPlaceholderArgs args) +183
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Helpers.SitecoreHelper.Placeholder(String placeholderName) +258
       ASP._sitecore_shell_client_Speak_Layouts_Layouts_Speak_Layout_cshtml.Execute() +2011
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +252
       System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +148
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +122
       System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +136
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +257
    
    [InvalidOperationException: Error while rendering view: '/sitecore/shell/client/Speak/Layouts/Layouts/Speak-Layout.cshtml' (model: 'Sitecore.Mvc.Presentation.RenderingModel, Sitecore.Mvc').
    ]
       Sitecore.Mvc.Presentation.ViewRenderer.Render(TextWriter writer) +729
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Render(Renderer renderer, TextWriter writer, RenderRenderingArgs args) +147
       Sitecore.Mvc.Pipelines.Response.RenderRendering.ExecuteRenderer.Process(RenderRenderingArgs args) +73
       (Object , Object[] ) +74
       Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +469
       Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22
       Sitecore.Mvc.Pipelines.PipelineService.RunPipeline(String pipelineName, TArgs args) +195
       Sitecore.Mvc.Presentation.RenderingView.Render(ViewContext viewContext, TextWriter writer) +331
       System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +375
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +88
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +776
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +776
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +81
       System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +36
    
    Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2558.0
[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/zGiQ7.png

I saw this article from the community sitecore but really not sure if why i encountered it at the first place. https://community.sitecore.net/developers/f/8/t/3979#pi214filter=all&pi214scroll=false 

Any ideas?

Update-1:
I found a similar issue in the stackoverflow. https://sitecore.stackexchange.com/questions/6201/experience-editor-server-error-8-1, but seems that is only for sitecore 8