Not seeing meeting responses from attendees outside my organisation

[KA-8A]

I’m not receiving meeting responses from

outside my organisation. Internal responses are fine, it’s just external. People have accepted but it’s not showing in the tracking details. Still notes them as having not responded. Any ideas? 

[#2]

There can be a number of reasons for that, best thing to do is to run a message trace and check for any messages from the (set of) recipient. https://learn.microsoft.com/en-us/exchange/monitoring/trace-an-email-message/message-trace-modern-ea...