Client Apps getting Authentication Errors -- Webmail Working Fine

Well, this is completely baffling. It happened a week or two ago and then the magic pixies worked their magic and if ‘fixed itself’. But now it’s happening again today:

I can send and receive email fine from the Roundcube webmail app. But my email client app on my computer, which up til now has been functioning fine too, is suddenly throwing up authentication errors every time I try and send an email --asking me to re-enter my password, which is not accepted. Even though it’s exactly the same one I’m using in the WebMail interface [I use a password manager, so there’s no scope for user error with the password].

Equally baffling. the exact same thing has started happening on my girlfriend’s email account too. Can’t send in client app. can send fine using webmail, with same credentials. And, just for even more larks, we’re both using different email clients: Apple Mail on her part and MailMate / Thunderbird on mine.

So has anyone any ideas at all why this can be happening? As I said at the top, it’s happened before and last time ‘fixed itself’. So I’m daring to assume the same will happen again now. But what could possibly cause MIAB to generate authentication errors when a desktop client app connects, yet perform normally when using the webmail interface?

Change the password in the admin app.
Reboot the box.

See if that helps.
Yes, I understand that the password works in the web app.

I’ll try that next time it happens. At present I’m seeing if another of my crackpot notions has any effect:

I’m on MacOS and looked in the Keychain Access app and found that, as well as the current MIAB passwords, there were lots of defunct passwords saved in there from when my mail was hosted by Google. It seems unlikely that this could affect anything with clients connecting to my MIAB. But just in case there’s any weirdness going on whereby the client apps sometimes retrieve the wrong password from the keychain I’ve deleted all the old ones. So let’s see how this pans out.

Looks like google backtracked for “non-business” customers. (which was me) although I’ve already deleted my account. Seems Ill likely never get it back and honestly, that’s probably OK. Seems that hosting your mail is not for the faint of heart but I’d rather do it at this point. I feel that google and big-tech was just spying on you anyways.

Yeah. Luckily that was announced just before I was preparing to undertake the other Herculean task of moving my huge photo archive off Google photos on my custom domain account and onto a regular one.

So now I can keep using Google Photos to backup my photos and host my own email via MIAB --I’d like to use something less ‘spywarey’ for photos too, but, unfortunately the alternatives are either poorly supported or even crapper than Google Photos. An added bonus is that I now have an extra 7GB or so storage available on my Google account, since removing my massive email archive.

MiaB installs nextcloud by default http://mail-in-a-box_URL/cloud
As long as you dont have a ton of users, nextcloud can easily save all your photos to it. There is even an app you can get for free for iPhone or Android to push photos up from your phone.

Aye. I know about NextCloud. I also use Jottacloud, Mega and Yandex Disc to store/backup some of my ‘stuff’. And, since I have Amazon Prime, I also checked out Amazon Photos. But, unfortunately, none of them [including NextCoud] integrate as well into the OS as Google Photos [because of its connection with Google Drive] … or make it as easy to keep things in sync across platforms, or share with other people.