"No worthy mechs found" when trying to relay email to Gmail using Postfix
Solution 1:
Ah-ha! Installing the libsasl2-modules package solved the problem.
Solution 2:
Running
sudo yum install cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain
helped me on Amazon AWS server.
Solution 3:
sudo yum install cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain
worked for me with Gmail relay setup (CentOS 7)