Hi Delphiniumdog,
Thanks for reaching out using Apple Support Communities. Here to help.
We understand you are getting an error message on your iPad and iPhone regarding your Gmail account. Just a few questions to help us understand the issue.
Is your Gmail account set up for Mail, Contacts, Calendar, or Notes on these devices?
When are you getting this error message? Is it occurring at random, or just when you try to access your Mail?
Can you access your Gmail account by signing in on their website?
If your password is working to sign in at Gmail.com, you may want to remove and add back the Gmail account to your iOS devices, as this may help establish a connection to the account and update server settings. In the below article, see the section titled 'Remove your email account and set it up again'.
If you can’t send email on your iPhone, iPad, or iPod touch
Hope this gets you in the right direction! If you still need help, feel free to follow up with more details.
Take care for now!