Weird mail issue, can't connect from some locations

I've had this issue since I moved my website from ServerA to ServerB about 3-4 months ago.

There's 2 locations (my home and my GF's home) where I cannot setup the email on a 3rd party client (IE; Thunderbird, Outlook or on my phone). When I try to enter all the information, it sets at "connecting to server" and then comes back saying it cannot connect.

But, if I go to another location (IE; Work) and try to set it up with the exact same information, it connects without any issues.

Once the account is set up, I can send/receive emails from any location.

I have no idea how to fix this issue. I've tried using multiple computers and get the same thing.


Anyone have any suggestions on what I can try? I'm 100% sure the information is correct (since I can 'refresh' the connection settings on my phone and it errors out at home even though it was successful at work).


The Domain is crossflame.com and the mail server is mail.crossflame.com

 

This is most likely the result of "Port 25 filtering" enabled by your ISP to prevent spam from originating from their network. You might try using SSL on a secure SMTP port like 465, and see if your results change from the places it doesn't work from.

 

As Zach mentioned, many ISPs will block port 25. Depending on how your server is setup you may need to use port 465 or port 587. Also I've seen some firewalls block insecure ports (110,143) and you may need to use port 993/995.

 

Ok, i'll give that a shot when I'm home.

Thanks!

 

Ok, partial success...

On my phone I've changed the connection to use port 143 and port 465 and it worked.
On my computer I tried the same thing and it didn't work. Only difference is that when I select 465 on the computer email client, it changes the security type to "SSL/TLS" while my phone has it as "None".

Does this mean I don't have SSL set up correctly?