If i remove TabId parameter from URL on any page it causes Object not set to an instance of an object error and page won't open.

Example:
With TabId parameter: www.mysite.com/News/tabid/36/language... works fine!
Without TabId param:  www.mysite.com/News/language/en-US/De... does not work and it returns error below.

This same error appears when i setup friendlyUrl rewritter of Ifinity which also removes tabid...

We're running dnn 5.6.

Does anyone else get this error when he/she removes tabid from url? What can we do get rid of this parameter?

Thank you all in advance,
Luka

Server Error in '/' Application.

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Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] DotNetNuke.Entities.Portals.PortalSettings..ctor(Int32 tabID, PortalAliasInfo objPortalAliasInfo) +70 DotNetNuke.HttpModules.UrlRewriteModule.OnBeginRequest(Object s, EventArgs e) +2449 System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +79 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +170