Acrobat X won't connect to update server on MacOS Sierra

Hello.

We have about 30 Macs, most of which run Acrobat X. Since we upgraded to MacOS 10.12 (and indeed 10.12.1) Sierra, none of them are able to connect to Adobe update servers. Upon checking for updates It always says:

"Cannot connect to Adobe update server. Please verify that you are connected to the Internet and check for updates again. Error 1042."

Reinstalling Acrobat doesn't make any difference.  Some of us have Acrobat XI or DC and those are fine.

Can anyone help?

Thanks in advance.