Hi @Mark Sutter
Welcome to our forum!
What is your account? Outlook.com or gmail.com or something else?
Did the issue occur on Outlook desktop client?
Did you send to all Gmail accounts, they receive a lot of replies emails, or individual accounts?
Based on my research, i did the following steps and everything works fine.
- Outlook.com account (signed in on Outlook client) sent a meeting to Gmail, Gmail could accept normally.
- Gmail account sent a meeting to outlook.com (on Outlook client), after replying on Outlook client, Gmail receives only one reply message to receive the invitation.
- Gmail A account (signed in on Outlook client) sent a meeting to Gmail B (signed in on web), B account could receive normally.
- Gmail B account (on web) sent a meeting to Gamil A (on Outlook client),after A replies, Gmail B receives only one reply saying that A accepted the invitation.
Everything seems to be running smoothly, to further confirm if the issue is more related to Outlook desktop client, you may try updating the client or re-adding your account to see if the problem is repeated, if not, it may be more related to users who use Gmail accounts, and it is recommended that they clear their browser cache or update the app to see if the problem persists.
Hope it helps.
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