Yup same problem for me too.
I’ve tried:
- Adding a new row from the GUI. Gives a “Saved Failed: Could not save row: Unknown error”
- Add a row from the server console
- Add a row to an empty table.
- Add a row to a table in a different app.
- Changing data in a table works as expected.
- Creating a new, blank app, adding a table and try to add a row in the GUI.
- Tried both normal and Accelerated tables.
- Checked I’m not exceeding my database quotas
Related post should be merged here.