After a pod restart (same image, no changes to previously working pod). No user can sign in to our CM instance (v10.1.3). The logs show the below error after a login attempt and I'm utterly stumped - any ideas? It's happened on two instances running separate images. I imagine it's something user related in the core DB?
ERROR Could not instantiate event handler. Type: Sitecore.Data.Fields.ItemEventHandler. Method: OnItemCopied (method: Sitecore.Events.Event.BuildConfigSubscribersFromConfiguration()).
Source: Sitecore.Events.Event.BuildConfigSubscribersFromConfiguration() at Sitecore.Diagnostics.Error.Raise(String error, String method) at Sitecore.Events.Event.EventSubscribers.Add(String eventName, XmlNode configNode) at Sitecore.Events.Event.BuildConfigSubscribersFromConfiguration() at Sitecore.DependencyInjection.LazyResetable`1.get_Value() at Sitecore.Events.Event.RaiseEvent(String eventName, Object[] parameters) at Sitecore.Data.Properties.PropertyStore.RaiseEvent(String name, Object[] parameters) at Sitecore.Web.Authentication.DefaultTicketManager.RemoveTicket(String ticketId) at Sitecore.Owin.Authentication.Pipelines.CookieAuthentication.SignIn.RemoveTicket.Process(SignInArgs args) at (Object , Object ) at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain, Boolean failIfNotExists) at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) at Sitecore.Owin.Authentication.Security.Cookies.DefaultCookieAuthenticationProvider.ResponseSignIn(CookieResponseSignInContext context) at Microsoft.Owin.Security.Cookies.CookieAuthenticationHandler.d__13.MoveNext() in /_/src/Microsoft.Owin.Security.Cookies/CookieAuthenticationHandler.cs:line 310
EDIT
On restarting the instance I think we have another clue, it's unable to start the core db agent
3168 10:34:16 ERROR Error while instantiating agent. Definition: core/sitecore/system/tasks/schedulestrue Exception: Sitecore.Exceptions.ConfigurationException Message: Could not create object from service provider . Config XML: core/sitecore/system/tasks/schedulestrue Source: Sitecore.Kernel at Sitecore.Configuration.DefaultFactory.CreateFromServiceProvider(XmlNode configNode, Boolean assert) at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, Boolean assert) at Sitecore.Tasks.Scheduler.Agents.DefaultAgentsConfigReader.Parse(XmlNode agentConfigNode)
Nested Exception Exception: System.InvalidOperationException Message: Unable to resolve service for type 'System.String' while attempting to activate 'Sitecore.Tasks.DatabaseAgent'. Source: Microsoft.Extensions.DependencyInjection.Abstractions at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider) at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, Object[] parameters) at Sitecore.Configuration.DefaultFactory.CreateFromServiceProvider(XmlNode configNode, Boolean assert)