Same issue with us.  We upgraded to 7459 last night from the previous production version 7242.  Everyone's EAS contacts are gone on their mobile devices.  This is on both Android and IOS devices.  The contacts are still on the server but were removed on mobile devices.  We have also tried removing and re-adding the EAS account which did not fix the issue.  This is a HUGE issue, we've been getting emails all morning.  No one knows phone numbers to call or text people.

Have your users go into webmail => Settings => Connectivity => Under Synchronized Devices => open and delete iPhone (EAS)

On the users phone, have them reboot the phone.

Under extreme circumstances, repeat the steps above, remove the EAS account for the iPhone, and reinstall. 

Chris, thank you that worked!  I also did hear from SM Support that the developers are working on the issue so hopefully we will have a global fix soon but at least I'm able to manually fix the clients that are desperate for their mobile contacts back.  Thanks again!

Hello. Thank you for these infos. We also start seeing customers opening tickets about lost contacts on their iPhone. I hope the global fix will be available soon, crossing fingers.

Thank you, everyone, for reporting this issue.  I have been able to replicate the issue when syncing an existing EAS connection on SM15 then upgrading that server to the latest build.  The device removes the contacts, passing back the existing sync key, and the server is not pushing the contacts back to the device.  We are investigating this behavior. I will help this thread updated with what we find.

A workaround in the mean time is to performing the following. Please note that the account MUST be removed from the device AND from the Sychronized Devices in the web interface.

Hello Robert, that's great news ! Thank you.

Hello, update to build 7468 solved the problem? Same error here :(