Couldn't reach server. Please double-check the server and port number.

[GoWilkes]

I found earlier threads on this, but no real solution.

I have all of my incoming emails forwarded to Gmail, then use my account's SMTP to send email. This works perfectly in Thunderbird and on my phone, but trying to set it up in Gmail (under Settings > Accounts and Import > Send mail as) gives me the error:

Couldn't reach server. Please double-check the server and port number.

I'm using the exact same setting as Thunderbird and my phone, which I double-checked by logging in to Webmail then clicking on "Configure mail client". I tried using SSL and non-SSL, and either had the same error or an error saying that the server couldn't be reached.

Any suggestions?

 

[24x7server]

Hello,

I think there is issues with the server firewall, Please try to disable your server firewall and check it again.

 

[mywhm]

try another port, for example 587

 

[cPanelMichael]

Hello

Could you verify if your server's firewall is blocking access to Google's IP addresses? You may want to install a firewall management utility such as CSF if you have not already done so.

Thank you.

 

[GoWilkes]

I think I got it to work! I had to add all of these to the firewall whitelist (which is CSF):

209.85.137.9
209.85.139.9
209.85.128.0/17

64.233.161.9
64.233.160.0/19

72.14.235.9
72.14.192.0/18

74.125.0.0/16

I still couldn't connect using port 25, but was able to connect using port 465 over SSL.

Hopefully this list of IP's will help future users. Thanks, all!

 

[cPanelMichael]

I am happy to see you were able to address the issue. Thank you for updating us with the outcome.