POSTMAN SMTP cannot match TLD against known list

I am using Postman SMTP plugin 2.0.11
I am having problems with sending email through the wp_mail() function. Most of the time it works ok, but sometimes it does not send the email and whips out this error to the log.
I am sending from site https://test.mydomain.info

‘~^(?.+?).mydomain.info$’ appears to be a DNS hostname but cannot match TLD against known list, ‘~^(?.+?).mydomain.info$’ does not appear to be a valid URI hostname, ‘~^(?.+?).mydomain.info$’ does not appear to be a valid local network name

This happens for about once in 15 emails. I cannot discover any consistencies on when it works and when not. It seems that WP somehow does not put the domain name together correctly? Where should I look for a solution?