Can't share Outlook 2010 Calendar

[JimmyRosa]

Hi All,

Users are receiving this error message when trying to share Calendars: 'error while preparing to send sharing message outlook 2010'

I have tested this with my account using OWA and I can share successfully using OWA but not Outlook 2010 client.

We are running Exchange 2010.

I've tried following some fixes on the net. Checked A Record on DNS server. An A record does exist.
I've run a test email configuration, but don't understand how to check what to look for exactly.
I've run a remote connectivity analyser test too, but again not exactly sure what I should be looking for.

Any help or advice, steps to check?

Cheers,
JR

 

[JimmyRosa]

Just wanted to add, we have a few users that have Calendars already shared from a few months back and these aqre still working.
The only thing that has changed since is that we have recently changed our ISP provider?

Thanks,
JR

 

[JimmyRosa]

Can anyone help on this please?


Kind regards,
J