Using APU's Gmail on an iPhone or iPad
To set up your APU Gmail account including calendar and contacts to sync with your iPhone or iPad please use the following steps:
Step 1: Go to Settings then select Passwords & Accounts (On later iOS versions, go to Apps > Mail > Accounts)

Step 2: Select the Add Account option

Step 3: Select Google

Step 4: Enter your full APU email address (including the "@apu.edu")

Step 5: This should relocate you to the CAS home page login in where you will enter in your regular APU credentials (without the "@apu.edu"), and then your email will be added.
Alternative Method
Download the Gmail App from the App Store and enter your full APU email address (with the "@apu.edu") - it should allow access to your APU email at that point.
