@ -1276,6 +1276,7 @@ Note that [Google Fi](https://fi.google.com/) is using a VPN too.
SMTP servers can reject messages for [a variety of reasons](https://en.wikipedia.org/wiki/List_of_SMTP_server_return_codes).
SMTP servers can reject messages for [a variety of reasons](https://en.wikipedia.org/wiki/List_of_SMTP_server_return_codes).
Too large messages and triggering the spam filter of an email server are the most common reasons.
Too large messages and triggering the spam filter of an email server are the most common reasons.
* The error *... Socket is closed ...* might be caused by sending a too large message / attachments
* The attachment size limit for Gmail [is 25 MB](https://support.google.com/mail/answer/6584)
* The attachment size limit for Gmail [is 25 MB](https://support.google.com/mail/answer/6584)
* The attachment size limit for Outlook and Office 365 [is 20 MB](https://support.microsoft.com/en-us/help/2813269/attachment-size-exceeds-the-allowable-limit-error-when-you-add-a-large)
* The attachment size limit for Outlook and Office 365 [is 20 MB](https://support.microsoft.com/en-us/help/2813269/attachment-size-exceeds-the-allowable-limit-error-when-you-add-a-large)
* The attachment size limit for Yahoo [is 25 MB](https://help.yahoo.com/kb/SLN5673.html)
* The attachment size limit for Yahoo [is 25 MB](https://help.yahoo.com/kb/SLN5673.html)