Every time I send emails, there is an error. How can I fix the problem?
The most common issues are caused by an incorrect DNS server address entered by the user. If you received a "Failed to query MX server of domain.com" message, check if the email address format is correct. A right format looks like: email@example.com. If it is correct, go to Settings > Detect DNS in order to detect your local DNS settings and check the troubleshooting provided by FlashEmailCast. If the problems persists, you need to contact the developer.
settings then copy the dns and copy it in the secondrey dns