Thunderbird 60.8.0 can't send emails via openxchange SMTP server
Hello everyone,
Openxchange SMTP server rejects email that shall be send.
smtp.openxchange.eu:587 STARTTLS
Error message: An error occurred while sending mail. The mail server responded: 5.7.1 Reject for policy reason. Please check the message and try again.
Given that it works fine via webmail and email clients like 'Em Client', the following can not be the issues: -IP address of sender, -blacklisted email address or domain -bad DNS records
As it works fine with other email clients like 'Em Client' I suspect that the issue is created by thunderbird itself that triggers the SMTP server to block.
Can you please advice?
Thank you