First, I suggest you keep VPN turned off until everything is working. Next, be sure you accept cookies at settings>privacy&security Then, I suggest doing one account and report status. I always recommend NOT including password during initial setup. That lets you know that thunderbird found the basic account information. Wait until prompted for password to enter it. Once everything is working, I recommend doing a backup of profile when thunderbird isn't running.

Hi David, Thank you for the swift reply. Greatly appreciated. We have moved a step closer, for which I thank you. Yes, there is a "however" coming... ;) However, whilst the account seems to have been accepted, the Inbox is empty and no folders or emails are being displayed - the only folder being Inbox. I followed your instructions and turned off the VPN. The Cookies were already set to "Accept cookies from sites" and to accept Third-Party cookies - Always. I used an App Password which seems to have been accepted. I have attached graphics showing that I didn't insert the password until requested, and the current state of play. Any suggested next step? Thanks for your help so far!

Peter

try highlighting the account, right click and select 'subscribe' and see if that shows other folders.

One of your pictures shows port 585 for the incoming GMX IMAP. It should be 993. Also, use 'normal password' authentication, not 'Encrypted password', and use the account password, not an app password.

https://support.gmx.com/pop-imap/imap/server.html

Besides the VPN, your antivirus might be blocking setup if it's not the built-in Windows Security. Run Windows in safe mode to bypass interfering startup apps, then add the accounts.

Thank you David and sfhowes.

Firstly, David: regretably, the "highlighting the account, right click and select 'subscribe'" didn't do anything to solve the issue. I'll attach a screen print.

Then, sfhowes: You are quite right about the port numbers. I had included that picture because I was trying to show the alternative ports and settings I had used beyond the default. Those port numbers had been given me by GMX, because I had also raised the issue with them.

So, the current status is that the account has been successfully added to Thunderbird, but no folders or emails have been synched - see image. The rest of my email accounts I have successfully added to the New Outlook Desktop app, which I don't really like because Thunderbird is a much better product, but needs must. Hopefully if we can resolve the issue, I can add them back into T'bird, and drop Outlook.

Thank you - I really appreciate your suggestions, and hope we can get to the bottom of this. Peter

Thank for providing this wonderful information.

At this point, it appears there is an error somewhere in the setup. My suggestion is to remove the gmx account, review help>troubleshootinginformation mail&newsmatrix to verify that it's gone, close and restart thunderbird, and then add the account again. That's my best guess, since you have the right setting. I also have gmx account and it is working properly.

Hi, Monday morning and back to the problems! sfhowes had suggested setting up the account in Safe Mode. I tried this in both Safe Mode and Safe Mode with Networking, with no success. I have attached a pic as I was unable to get screen print to work (par for the course at the moment :) ). You'll have to zoom in a bit on the pic to see any details. David, Also tried your suggestion, but once again nothing doing. Given it has taken a while to get to this stage you won't be that surprised that I have set up the rest of my email accounts In the cut down Outlook Desktop app, so I don't have to open them all in different web pages. I too, have a secondary GMX account (this one isn't used very much), but it did get accepted within Outlook after a couple of tries, and is working fine, but my primary GMX account (basically used for all business emails) is still not being accepted by Outlook either, which to me is pointing at it being something in the GMX server metadata behind the scenes that I have no control over. I'm not confident that GMX helpdesk will resolve this, as some of their answers so far have been a bit whimsical, so I think for the time being I'll just have to use a browser to deal with this account. The recent comments you folk have been suggesting have sounded increasingly forlorn, so I would guess there isn't much more you can suggest (absolutely no criticism intended, because there has to come a point where options run out). Thank you for all your suggestions - they have been useful, even if they didn't solve the problem.