Using New Outlook on Windows for personal email, calendar, and contact management
Having same problem - Win 10 New Outlook version 1.2025.129.300 (Production) & version 1.2025.205.100(Production) stopped receiving/sending emails Feb 5. No error messages.
I had similar issue and reached out to MS support who was very helpful. I had deleted the affected account in Outlook; then go into the web access for that account, under security section, create "app password." THEN go back into Outlook and re-added the affect account back using the "new" app PW. This worked for me and Outlook started syncing all accounts again.