I’ve got my Monzo added to Chase, and have added many new accounts over the years, never seen that payee error before.
I’ve also never had a blocked payment out (or in) before, although sometimes it does stay pending (even up to 2 hours), especially if I’m paying a brand new account I’ve just opened somewhere else.
The Chase app is okay in my opinion, but it does have a few bugs that need ironing out. The most annoying for me is on iOS when opening the app sometimes it takes 10-15 seconds for Face ID to scan, and if you put the code in before that and it lets you into the app, it still does the Face ID scan. I’ve also noticed a new bug in the recent updates where if you change to the savings tab too quickly after opening the app, it stays there and you cannot go back to the spending tab, force close is needed.
I did see on Reddit a few people reporting the credit card application was broken, and they were actively speaking to Chase about it, which maybe why it’s been pulled for now.