Syncing with Proxy network servers

[tajhad 2]

I wonder if anyone can help.

I run a mac through a windows proxy server (a school). Evernote synced beautifully with everything until a couple of weeks ago.

Now Evernote won't sync with my school iMac. It will sync in windows (using Parallels) but won't sync on the mac side. 

My IT are no help ("its because it is a mac  - you should use OneNote instead !"). Are there any particular ports or certificates Evernote needs that I can tell them about ? They claim they haven't blocked anything.

 

Thanks in advance.

 

Terry