Updated FAQ

FAQ.md

@@ -85,6 +85,14 @@ For authorizing:
 * Comcast/Xfinity: please check if [third party email access](https://www.xfinity.com/support/articles/third-party-email-access) is enabled
 * Mailbox.org: with two factor authentication you'll need to use [an app password](https://kb.mailbox.org/en/private/security-and-privacy/application-passwords-for-external-programs/) ([German](https://kb.mailbox.org/de/privat/sicherheit-und-privatsphaere/applikationspasswoerter-fuer-externe-programme/))
 
+**Important:**
+
+*There is a good reason why the app warns against using a VPN:*
+With a VPN, you share a single network address with many people, and not all of those people will behave properly all the time.
+Most email servers automatically block network addresses when abuse is detected, for example, when someone tries to send spam.
+That is why a VPN is often problematic for email. Someone else's misconduct can affect you.
+So if there are authentication problems while using a VPN, either when configuring or using an account, try turning off the VPN, or create an exception for FairEmail in the VPN app.
+
 Please see [this FAQ](#faq22) for common error messages and solutions,
 and please see [this FAQ](#faq207) in case of '*Authentication failed*' or similar.
 

index.html

@@ -109,6 +109,8 @@
 <li>Comcast/Xfinity: please check if <a href="https://www.xfinity.com/support/articles/third-party-email-access">third party email access</a> is enabled</li>
 <li>Mailbox.org: with two factor authentication you’ll need to use <a href="https://kb.mailbox.org/en/private/security-and-privacy/application-passwords-for-external-programs/">an app password</a> (<a href="https://kb.mailbox.org/de/privat/sicherheit-und-privatsphaere/applikationspasswoerter-fuer-externe-programme/">German</a>)</li>
 </ul>
+<p><strong>Important:</strong></p>
+<p><em>There is a good reason why the app warns against using a VPN:</em> With a VPN, you share a single network address with many people, and not all of those people will behave properly all the time. Most email servers automatically block network addresses when abuse is detected, for example, when someone tries to send spam. That is why a VPN is often problematic for email. Someone else’s misconduct can affect you. So if there are authentication problems while using a VPN, either when configuring or using an account, try turning off the VPN, or create an exception for FairEmail in the VPN app.</p>
 <p>Please see <a href="#faq22">this FAQ</a> for common error messages and solutions, and please see <a href="#faq207">this FAQ</a> in case of ‘<em>Authentication failed</em>’ or similar.</p>
 <p>Related questions:</p>
 <ul>