Unable to connect to smtp.zoho.eu

A couple of days ago, I tried to send an email using Mozilla Thunderbird. Receiving emails wasn't a problem, but the connection to the smtp.zoho.eu server couldn't be established.

I read about this problem in the forum, unfortunately the zoho employees asked to send them an email at support@zoho.com. So, I did that aswell, including screenshots of configuration and a tracert.

I didn't hear back from them since then. Is it usual that they don't reply/don't care?