Environment
One Identity Manager 9.2.1
Portal
Angular Web Portal. Installed from OOTB installer.
Server OS
Server 2022
We have been getting the below error when users are trying to login to API Portal, The Login portal keeps on Loading and in the APP_Data-> LogFile I see the below error
2025-09-05 15:54:59.1199 ERROR ( WebLog ) : An error occurred while processing the request: GET apiportalurl.test/.../entityschema System.Exception: An error occurred while processing the request: GET apiportalurl.test/.../entityschema ---> System.FormatException: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.
at System.Convert.FromBase64_ComputeResultLength(Char* inputPtr, Int32 inputLength)
at System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength)
at System.Convert.FromBase64CharArray(Char[] inArray, Int32 offset, Int32 length)
at QBM.CompositionApi.Session.ClientDataExtensionMethods.GetDataEncoded[T](IClientData data, String key)
at QBM.CompositionApi.Session.SessionProvider.<GetSessionGroupAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at QBM.CompositionApi.ApiManager.MethodRequestHandler.<GetSessionAsync>d__19.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at QBM.CompositionApi.ApiManager.MethodRequestHandler.<BuildQueryRequestAsync>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at QBM.CompositionApi.ApiManager.MethodRequestHandler.<SendAsync>d__16.MoveNext()
--- End of inner exception stack trace ---
Behavior
If I delete the Cache folder under APP_Data folder and restart IIS then it works fine for a sometimes.. then again the above error.
C:\inetpub\wwwroot\api\App_Data\Logs
C:\inetpub\wwwroot\api\App_Data\AssemblyCache
Any help would be appreciated.
