Getting Gmail in Apple Mail on AT&T

This issue began with release 7.0.1.

The issue is:

- using Apple Mail

- with a gmail LDAP account

- sometimes, upon opening mail, I get an error message twice indicating my username and/or password is incorrect (the second appears almost instantaneously after the first--both are open at the same time)

- this seems to occur most often when I am using AT&T with no wifi, but does occur occasionally on wifi.

- the rest of the time, the mail works fine.

In addition (and may not be related), there are many times when my phone will show no service while sitting on my desk in my home. At other times, in the same place, it will show three of four dots.

I have deleted and re-setup gmail.

I have replaced the SIM card.

Can't tell if it is an iPhone issue, a gmail issue, an AT&T issue, or is multiple issues. Any ideas?