Office 365 contacts cant syncronize

[inknow]

We have a previously 3CX pbx that has been deployed 3 years ago, now we want to integrate it with Office 365 so each user can get its contacts on their personal phonebook, extensions had its assigned number, connection has been set OK, but contacts and calendars didnt sync. How to make it work, 3CX support days that i have to clear all extensions and let the sunc procees create this from scratch but hen al extensions number should be changed.

 

[NickD_3CX]

You can try the instructions in the guide here: https://www.3cx.com/docs/office-365-integration/

You don't need to delete all extensions, the only thing you need to make sure for this to work is that the email of the extensions you want to sync in the 3CX Console, match the email or principal ID of the corresponding users in O365 Console.