How to stop repeated alternating accept decline messages being sent to a meeting organizer

Hi @Mike Murray

The repeated acceptance and decline messages may be caused by a synchronization issue with Outlook or another device connected to your account.

Here are a few steps you can try:

1. Sign out and sign back in through Outlook on the web

• Open a browser and sign in to Outlook on the web.
• Select your profile picture or initials in the upper-right corner, and then select Sign out.
• Close all browser windows.
• Reopen the browser, sign back in, and allow the mailbox and calendar to finish loading.
• Also, on the https://outlook.office.com/ click F12 to open DevTools, select - Application and find the local storage cache right click and select Clear  
• 
• Still in the left pane, locate the https://outlook.office.com/ link under Cookies, right-click on it, and select Clear.  
• 

Please note that clearing the cookies and local storage will sign you out and may reset some Outlook website preferences.

2. Reset New Outlook’s local app storage

• Fully close New Outlook.
• Press Windows key + R to open the Run dialog box.
• Enter the following command and press Enter: olk.exe --devtools
• 

3. Reset or reconnect the affected account

• In New Outlook, select the Settings icon in the upper-right corner.
• Go to Accounts > Your accounts.
• Select Manage next to the affected account.
• 
• Select Remove and then follow the prompts to remove the account from New Outlook.
• 
• Restart New Outlook.
• Add the account again and allow the mailbox and calendar to finish synchronizing.

4. Repair the New Outlook app 

Try repairing the New Outlook app as well, as this should not affect its data or settings. If the issue persists after the repair, return to the same Advanced options page and consider selecting Reset.

Please note that resetting the app may remove locally stored app data, so you may need to sign in again or reconfigure some preferences.

For more details, please refer to: Repair an Office application

I hope these steps help resolve the issue effectively. If the problem persists, please feel free to reply with any additional information.