@aakash Although I have not encountered this issue but I can say that the error messages in Cloudworks are somewhat misleading. Also I have seen that it takes a bit of time when you try to create an Integration process and connect to Workspace / Model / Process for the actions to show up but it does show up after a bit of wait. I would say, you can try couple of times to see if the issue still persists and then raise the issue with email@example.com as suggested by @alexpavel
I raised the issue with Anaplan. The issue persisted on a weekend and got resolved on Monday. I confirmed with Anaplan, they didn't make any changes on their part, neither did I make any changes. Although the issue is resolved now, no one has any idea what caused it and what solved it.
Interestingly, I've run into the same thing recently. There were intermittent errors, followed by success, with no changes to the actual integration. Not sure if they're working on something in the backend.