Send Test Email -> no email. now what?

I installed this plugin on recommendation of my webhost (inmotion) because my multisite installation stopped sending mail on form submissions for no apparent reason. It HAD been working fine.

I tried 3 different form plugins, none send mail.

Webhost tested server, it sends fine. They recommended this plugin.

I installed Easy WP SMTP and configured it. When I send a test email, nothing happens. No error message. No email.

What am I missing?

Oh – I tried it using “Network Activated” and on one site only. Same difference.