Voicemail notification not working

I need help with voicemail notifications. I bought admin pro last night and got my smtp setup, I’m using Gmail and got email tested ok by clicking on debug and sent a test email. However when I test voicemail notification I don’t receive any emails.
I have centres the recipient email under the user settings, but no email is received. I’m using FPBX 17 and is a fresh install with only a few users.

You should see some clues in /var/log/maillog when you attempt to send an email.

Thanks @lgaetz. I’ll check it out and let you know.
Well, I suck at Linux, I couldn’t find the path. But while trying to change the http ports and installing a certificate, I screwed up badly and broke it. So I rebuilt the VM and this time Voicemail notification worked. It took so many attempts to get the FreePBX install to work, it’s not very reliable, the install failed 4 times. Rebuilt Debian twice.
But is all good now.