iPhone email not syncing

I have uninstalled and reinstalled my xfinity email over the last few days. It was the only way to reestablish a connection in the mail app in my iPhone 17 pro and my xfinity account. Now it will pull in messages, however it won’t sync up with the server. I have no issues with my iPad. What can I do to correct this?  Please don’t tell me that I have to access the mail through the internet.