Outlook Calander Synch between PC and iPhone stopped working

I have Windows 11 version 22H2. I have Office 365 Outlook installed on my PC, and the Outlook app installed on my iPhone 11. I used to be able to synch calendar entries between the Outlook calendar on my iPhone and the Outlook calendar on my PC. But today I noticed that they are not syncing. On the iPhone do I need to use both the iPhone native calendar and the Outlook calendar, or can I just use the Outlook calendar? I have checked my iPhone to be sure that the Outlook calendar is the default for new entries. What else can I check? Thanks

Hi I have this issue, have you been able to resolve the Sync problem.