Mail app shows white screen then exits
I'm using Mail to access Exchange server and Gmail accounts on my iPhone 8+. Everything was working fine but yesterday I clicked on a large folder inside my Exchange mail tree, and the window went all white (no emails shown). From then on, every time I activate the Mail app, it shows a white screen for about 5 seconds and then exits. The Mail icon on the home screen shows red numbers (new incoming emails) but I can't see anything in Mail. I've rebooted the phone and even accepted the latest iOS update, thinking that might reset it, but no luck. I understand I can wipe the whole phone and restore, but I'm hoping someone knows how to fix this without that drastic step - why is Mail crashing and what can I do?