Hello Team,

Getting "a socket operation failed because the destination host was down" error when trying to read email from Gmail account through IMAP.

We have used the developer licences on another instance and not faced this issue.

Currently we are working on trial account as procurement of the licences is pending for this instance.

Please help!

It is likely that your connection to Gmail server has a problem.
Please make sure outbound 993 port is opened in your router or firewall.

You can do a test like this:

https://www.emailarchitect.net/eagetmail/kb/csharp.aspx 

Please see troubleshoot section and please test the imap.gmail.com 993 port by telnet.

Hello Ivan,

First it was giving connection could not be established error. When we opened IP ranges from 72.125.0.0 to 72.125.255.255 and opened port number 993 connection issue was resolved.

Have tried telnet impag.gmail.com 993 and it is getting connected now.

But when running it through code it gives this "a socket operation failed because the destination host was down".

Please help!

use open 993 port to any IP and try it again, because Gmail IMAP4 server IP addresses are variable and not limited to 72.125.*

Hi Ivan,

Have found what the problem is.

After i have removed server hardening configuration it is able to communicate to Gmail.

Please confirm if there is any particular configuration that i have to not do, since to add it to our company domain we have to perform server hardening.

Please help!

Thanks

Could you please add an outbound rule in your firewall to allow your application (.exe) from any Local IP/any Local port to Any Remote IP and 993, 995, 110, 143 ports.

I thought that should be OK.