Whenever i tried to trigger `InitializeEnvironment` Postman script.. 
    
    {{OpsApiHost}}/{{OpsApi}}/InitializeEnvironment(environment='{{Environment}}')

I always get below as a response.

    {
        "@odata.context": "https://localhost:5000/CommerceOps/$metadata#Commands/$entity",
        "Id": "7d681424004f4c80850d0c4e19352eeb",
        "ResponseCode": "Ok",
        "Messages": [],
        "Models": [],
        "ActionUrl": "",
        "TaskId": 446547,
        "Status": "WaitingForActivation",
        "IsFaulted": false,
        "IsCompleted": false,
        "IsCanceled": false
    }

And i think, that is the reason why my environment is not properly initialized.

Update 1: Added logs

> 18 19:31:09 INFO Request starting HTTP/1.1 GET
> http://localhost:5000/commerceops/InitializeEnvironment(environment='ArvindAuthoring')
> 18 19:31:09 INFO Successfully validated the token. 18 19:31:09 INFO
> AuthenticationScheme: "BearerIdentityServerAuthenticationJwt" was
> successfully authenticated. 18 19:31:09 INFO AuthenticationScheme:
> "Bearer" was successfully authenticated. 18 19:31:09 INFO
> Authorization was successful for user: "sitecore\Admin". 13 19:31:09
> INFO Executing action method
> "Sitecore.Commerce.Core.CommandsController.InitializeEnvironment
> (Sitecore.Commerce.Core)" with arguments (["ArvindAuthoring"]) -
> ModelState is Valid 13 19:31:09 INFO Executing ObjectResult, writing
> value "Microsoft.AspNetCore.Mvc.ControllerContext". 13 19:31:09 INFO
> Executed action
> "Sitecore.Commerce.Core.CommandsController.InitializeEnvironment
> (Sitecore.Commerce.Core)" in 13.4489ms 13 19:31:09 INFO Request
> finished in 33.8218ms 200 application/json; odata.metadata=minimal;
> odata.streaming=true; charset=utf-8 28 19:31:09 INFO
> Management.block.ValidateSitecoreConnection: Validating Sitecore
> connection: Url=https://storefront.local, Environment=ArvindAuthoring.
> 28 19:31:09 INFO SQL:blocks:ValidateSqlConnection: Validating Entity
> Store SQL connection: Environment=ArvindAuthoring 13 19:31:10 INFO
> Pricing.block.InitializeEnvironmentDefaultPriceBookBlock.InitializingArtifactSet:
> ArtifactSet=Pricing.DefaultPriceBook-1.0 28 19:31:10 WARN
> CtxMsg.ValidationError.BookNameAlreadyInUse: Text=Book name
> DefaultPriceBook is already in
> use.|Shopper=|Shop=|Correlation=924d5a55e5e747ada5bcac7ebdcd4d7c 26
> 19:31:10 INFO Management.GetCommerceTerms./sitecore/Commerce/Commerce
> Control Panel/Commerce Engine Settings/Commerce Terms/System
> Messages|en 13 19:31:10 INFO
> Management.block.getitemsbypath./sitecore/Commerce/Commerce Control
> Panel/Commerce Engine Settings/Commerce Terms/System Messages|en 13
> 19:31:13 ERROR PipelineAbort:Book name DefaultPriceBook is already in
> use. 13 19:31:13 ERROR
> Pricing.block.InitializeEnvironmentDefaultPriceBookBlock.Error:
> Message=The price book can not be null.

Any clue?