Using Outlook for iOS for personal email and calendar management
Hi @Cynlane ,
Thanks for writing your query.
Syncing errors may may mean you need to update your Outlook app on your iphone/ipad. Please try that if not done already. Once done and if the issue persists, please use Outlook on a desktop browser to delete junk emails and emptying deleted emails. If messages can be deleted in Outlook.com but continue to appear on the iPhone, open Outlook for iOS, go to Settings, select the affected account and use Reset Account. You can also remove and re-add the account.
Sharing a step-by-step guide in a documented response for your reference:
Some more info if you want: https://support.microsoft.com/en-us/outlook/install-mobile/troubleshoot-outlook-mobile-issues
Hope this was helpful. Please reach out if you have any other queries.