Honestly, I think the correlation IDs are for MS support. I think they use them to dig through log files. I don't have a paid cloud service, so this may not apply. Typically if I can't save, something is hung up in the background. If you made changes to a subflow, and you don't want to lose them, each subflow can be copied and pasted to text. This text can be copied and pasted back into PAD; the painful part is you have to do it per subflow.
Close down PAD, then open Task Manager, find PAD, right click, End Task. Now, reopen PAD, try to make a change to a flow and save it. If it is still not working, I would make sure that you are actively logged in to the cloud so it can reestablish any connections there. Absolute last resort would be reinstalling PAD.
Best of luck!
