English please.

Hello, I have a problem. I have Outlook running and my e-mail synchronization works fine. When I start firefox the synchronization (sending and receiving e-mails) stops working. If I restart Outlook with firefox running, the problem disappears. According to Microsoft, Firefox is the problem:

"It is possible that the module that changes the VPN connection built into FF performs some non-standard tunneling of information, which interferes with the synchronization of the mail of this particular mail client."

The above information from Microsoft.

this problem appeared on several computers about 3-4 weeks ago. Only now have I linked the fact that causes the outlook problem.

Are you on VPN having this issue? Who are you using for VPN? I don't understand "When I start firefox the synchronization (sending and receiving e-mails) stops working." Do you mean the website is not updating? You also mentioned "mail client", you are on the website accessing email right?

I don't use VPN. The message with "VPN" is a message from microsoft that this is how firefox affects outlook. After running firefox. Send and receive on outlook stops working. Microsoft support says Firefox is causing this problem. This problem occurs on all computers in the office.

I have a Hotmail or Outlook account and have no issues. Can you post a similar screenshot showing the issue. Have you tried Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

Also, have you tried clearing the browser cache? https://support.mozilla.org/en-US/kb/clear-cookies-and-site-data-firefox

I have to prep for work, but I'm sure someone will chime in. Later ;-)

I am sorry that I did not write immediately. Firefox affects the program Outlook. Not for the browser version