MS Access unable to save backup or accde

[Petrol]

I have a problem very similar to, but not identical with, one I had previously - "Access unable to save backup or make .accde". For some weeks now when I use File>Save As>... >Save As (where ... can be either "Back Up Database" or "Make ACCDE" ), Access just keeps asking for the database password over and over. If I keep entering the password, then typically
(1) If I have chosen "Back Up Database", then
- after the second request it will ask for the file name and folder to save into,
- after the 4th request it will say "Not a valid password", and
- after the 5th it goes away and appears to work and then reopens my database at the main menu.
(2) If I have chosen "Make ACCDE", then
- as soon as I click the second "Save As" it asks for the file name and folder to save into,
- it then starts repeatedly asking for the password, which I enter each time,
- after the 6th request it will say "Not a valid password", and
- then says Microsoft Access was unable to make the file.
In either case there is no sign of the requested file having been made.

The password I enter is valid. (If I deliberately enter an invalid one it invariably says Not a valid Password).
I am using up-to-date 32-bit Access 365 under Windows 11 22H2.
I have tried things like decompiling and recompiling (it compiles cleanly), rebooting, running a registry cleaner, and doing it on a different computer.

In the previous episode a few months ago the problem went away by itself, but only after several frustrating months.
Any suggestions?

[Petrol]

I'm not sure whether Markopalme's answer above was intended as a reply to this post, or was it accidentally posted to the wrong thread?

Anyway, I finally fixed the problem by laboriously copying every object from the original database to a new one, stopping every now and then to try to recompile (make accde). Never did find out what caused the original problem, but the copied DB works fine.