The solution was that he forgot to assign workspace permissions to these new users coming from the second domain and they therefore were not allowed to log on. Once he created a group, added the workspace user permission to it and then assigned it to all these users they could log on.
I am able to login into workspace but not able to submit the PDF forms?
When I submitting the form getting the below error
DSCError: ComponentID= DSC ErrorCode= 3 MinorCode= 0 Message= Invocation error. ErrorMessage: Invocation error. caused by: ALC-WKS-005-026: Access denied: access permission not assigned to user ""
I can only guess - maybe your users do not have the Services User role which gives permissions Service Invoke and Service Read. Or the service you are submitting to is restricted in access.
If access to the service is restricted it could also exclude the Administrator. Is this the standard submit inside workspace or are you submitting to a custom service? It is very difficult to determine what the problem is from here. Does this happen with all workflows?