Unable to email from iPhone 11

My iPhone 11 suddenly stopped allowing me to email. I'm getting a message stating that Unable to send address invalid. One minute I was able to email from Camscanner to my gmail account and then I was not. It was in the middle of the day, so no upgrade was going on. I am currently at iOS 14.4. I have tried rebooting, deleting my email and adding it back, etc. The first time I rebooted I was able to email one of the messages in my outbox, but that was it. I am out of ideas. It is imperative that I am able to email from my phone so that I can scan documents to put into Google Drive for remote teaching. Please help!