There was a problem while sending a test email

Replies: 0

There was a problem while sending a test email. Related debugging output is shown below:

Versions:
WordPress: 4.9.2
WordPress MS: No
PHP: 7.1.13-1+ubuntu16.04.1+deb.sury.org+1
WP Mail SMTP: 1.2.5

Params:
Mailer: mail
Constants: No

Server:
PHP.mail(): Yes

Any solution?