Hey,
Are you trying to connect this account using IMAP or POP? The new Outlook app is pretty picky and has historically struggled with POP accounts compared to the classic version.
Since sending works but receiving fails, it almost always points to a mismatch in your incoming server port or encryption method. Do you get a specific error code when it tries to sync the inbox? Also let me know if you can see new emails arriving fine when you check through your provider's actual web portal.