Outlook365 Vivaldi Email Socket Timeout

DarrenBollman

Everything was working fine until recently, my emails have suddenly stopped sending, the reason given is because of a socket timeout.

Incoming emails are fine.

my outgoing server is smtp.outlook365.com:587
I'm using OAuth

I've pinged the server in Command Prompt, and it receives all packets fine.

so it seems to be correct.

anyone know of anything I can try to fix this issue?

DoctorG

@DarrenBollman I have no Outlook365 account to test.

Your issue could be caused by a security tool (Internet Security, Mail filter proxy, Antivirus) on your PC blocking the port.

If you check Vivaldi Settings → Mail. selct the added account and look below Outgoing Server at Connection Security did you had tried with StartTLS?

Pathduck

@DarrenBollman Hi, according to the documentation you should use smtp.office365.com. Unless maybe this is some corporate setup with maybe a proxy?

https://support.microsoft.com/en-us/office/pop-imap-and-smtp-settings-8361e398-8af4-4e97-b147-6c6c4ac95353

From here your address doesn't even resolve:

$ nc -v smtp.outlook365.com 587
nc: getaddrinfo: Name or service not known

$ ping smtp.outlook365.com
Ping request could not find host smtp.outlook365.com. Please check the name and
try again.

$ nc -v smtp.office365.com 587
Connection to smtp.office365.com 587 port [tcp/*] succeeded!
220 GV3P280CA0046.outlook.office365.com Microsoft ESMTP MAIL Service ready at Wed, 14 Sep 2022 12:14:32 +0000

DoctorG

I checked with OpenSSL and saw that smtp.office365.com on port 587 needs use of StartTLS, it does not work with SSL/TLS over port 587.
But this is a Microsoft restriction, not a Vivaldi issue.

DarrenBollman

Apologies, i had typo'd the outgoing server as smtp.outlook365.com.

i do indeed have it set as : smtp.office365.com and i am using StartTLS

DoctorG

Does smtp.office365.com over port 25 with StartTLS work?

Pathduck

@DarrenBollman OK, do you have some network troubleshooting tools available? netcat, openssl or even good old telnet can help diagnose timeouts. If you can do a connection test from the command line, it will show if this is specific to Vivaldi (which I doubt) or your system in general.

You said you used ping but this only sends ICMP packets so won't tell if the server replies on a TCP port. Try a:
telnet smtp.office365.com 587
Windows telnet doesn't give good feedback, you'll usually get a black screen if the connection succeeds and can use Ctrl+^ to exit.

Is your system using a proxy server or VPN?
Other security tools?
Do you have the possibility to test in other mail clients, Thunderbird, even the very basic Windows Mail?

It might also be it's the connection to the OAuth server that times out, but that should be a regular https connection (443).

DarrenBollman

Changing to port 25 seems to have done the trick. Ill keep an eye on it tho, and update as and when.

Thanks for the help thus far.