If anyone thinks all reboots are the same just know they are not. There are multiple ways to reboot. I tried them and the issue came back. I forgot about how to force reboot @wacwacextreme suggested. It is the only force reboot that worked for me.
One note: after quick pressing the volume up button and then quick pressing the volume down button, I pressed and kept holding the power button down past the slider to turn the phone of off until the screen went black, and then the Apple logo appeared. Then I let off the power button while the phone finished rebooting. All has been fined since.
Since then, the mail issue has not reoccurred
If you tried this, and it worked for you too Reply to @wacwacextreme posted solution thanking them, or reply here with a mention to them.