inconsistent email notification

I have two users listed on the email notification for orders. The first email listed receives notifications all the time. The second email (separated by comma) almost never receives them (although they sometimes do). the second email is a gmail address and we've checked the spam folder. please help and advise what we can do! thanks

Hi,

Have you separate the address with a comma "," ? and Without space ? in the emails configuration ?
Thanks to check the validity of the email address, this should work.