CMS Made Simple Forums

Hi all, i've configured Newsletter made simple and i'm able to send newsletters via my GMail account. Everything is fine if the list contains 3-4 email recipients, but for 400 users it seems to timeout. I'm running the job by clicking the link on the Calguys Job processing manager. I have every setting on default. Is there any other way i should be doing this, are there any settings i can try?

CMSMS 1.11.6
NMS 2.7.2

Gmail has some strict rules sending bulk email.

See Bulk Senders Guidelines on https://support.google.com/mail/answer/81126?hl=en