I have several email addresses on a domain for which I'm using Zoho mail.  I mostly check my mail either using Outlook on a Windows 10 computer or using the native iOs Mail app on my iphone.  Since I have 2-factor authentication turned on, I have a dedicated password for the email apps.

Sporadically, maybe 2 or 3 times a month, when checking mail, I get a message that the password on one of the email addresses is wrong, and it refuses to get the email for that address.  It's always the same address, and has never happened for any of the other addresses.  Eventually, after some hours (has been as long as a day), the error message disappears and things are back to normal.  It always happens on both devices at the same time, which leads me to believe that it's a Zoho problem, not something local to my setup.  When it happens, there's never a problem getting email on the Zoho website or on the Zoho iPhone app.

I've tried changing the password and that made no difference.

Any suggestions?