"Unable to connect SMTP server"

"Unable to connect SMTP server"

Hello,

First of all, thank you for your wonderful service. I love everything about it and I was very happy with the changes you introduced in the last few months.

However, I am having a problem with one of the external email accounts that I use in Zoho. Last Thursday, it stopped sending emails, and I was getting the following error:

Reason:sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: timestamp check failed. Your Email has been placed in outbox for retrying"

I tried to login via webmail and got the "untrusted connection" screen, and I noticed my webhost's security certificate had expired that same day. I wrote them and they fixed it within a few hours, and then when I browsed to my webmail page I didn't get the "unstrusted connection" screen anymore. But I still couldn't send emails from that account using Zoho, I always got that same error. So I tried to change the "send mail" option to "Zoho SMTP" so I could at least reply to emails while the issue was being solved, but I got the following error:

Sending failed;Reason:553 Relaying disallowed

And now if I go back to the mail settings to try and change it back to "Custom SMTP" (with SSL), I get the following error:

Unable to connect SMTP server:mail.xxxxxxxx.com, Port465

Through all this time, I didn't have any trouble receiving emails. And when I tried adding this email address in a Gmail account and sending emails from there (via my server's SMTP), it worked.

Can you please help me? Thank you.