Why do all my emclient emails to gmail accounts fail?

I cannot get emclient to send to gmail accounts. This is a very intermittent problem, and reading threads seems to have been a known problem for a while. This used to be very occasional, but now happens all the time. As it is causing huge problems, what do I do?

Can you provide the error?

You will find this in Menu > Operations > Log tab. Look for an SMTP error.