"no password provided for" error
I have a newish iPhone 12 running v15.5. Went to change passwords on two email accounts (other domain). First one was fine. Second one throws the "No password provided for" error. Both accounts were working fine previously. Both accounts have the same settings. Both accounts work fine from laptop client and webmail settings. The email provider is not the issue here. The iPhone software has a problem.
It's pretty clear from the community responses that quite a few people have seen this error and have been unable to fix the problem. What's the actual fix?