Can't login to facebook messenger from iPhone 12. Constant error message

Please help. I can't login to the facebook messenger application on my iPhone 12. Both the phone, the regular facebook app, and the facebook messenger app are up to date. I've tried uninstalling, reinstalling, restarting, and resetting the iPhone. Nothing works. Constant "Error- Unable to complete request. Please try again later." This has been going on for weeks. One interesting clue is that I can't go to the facebook website on Safari or Chrome browsers on the iPhone either. The page won't load even though it loads fine on my MacBook. Something about facebook and my iPhone just isn't getting along. I'm trying to sell some things on FB marketplace and missing these messages is costing me money. Please help