Hi @Anonymous,
Please take a look at Office 365 Admin Center, check the user licenses information from there.
Make sure the Microsoft Flow Plan 2 is assigned to the user.
Besides, please also take a check for the connections used for the Action added in your flow. Such as the SQL Server Connection, and the action followed.
I just tried the Common Data Service trigger, and the flow could be saved from my side, which made me think the issue should be caused by the other Actions you used in your flow.
Regards,
Michael