problems sending email with google mail

Have a customer with a paid Pro version (7.1.3) of EM Client that is having serious issues sending using Gmail (google mail)…
His computer goes between several offices and when he leaves one and goes to another his mail stays in the outbox and will not send out…
The only way we have been able to resolve this issue in the past is to remove EM Client and all sub-directories and then reinstall a clean & fresh version of EM Client.
HELP! Got him on to EM Client from Outlook and if we cannot get this resolved he will need to go back - we do not want to support that!
Thank you in advance

Update info on computer
Computer is:
HP Spectre 360
256 GB SSD
Win10 Pro

EM Client Version is:
7.1.30794.0 (latest rev)

Have tried to reset IMAP SMTP Ports (587 & 465) and SSL & TLS without any luck
Had to reload the program just today 6th time in just a few weeks

I use port 587 and “Force usage of SSL/TLS”.  Works perfectly.

While GMail recommends 465 - SSL or 587 TLS/STARTTLS, I use 25 and “Use SSL/TSL if available”. Works perfectly. :slight_smile: