Hubshare issues on MacBook Air laptop

Hello, 

One of our external users is complaining that he can't see our Hub since December.  It seems like the page does not load properly because he says that "It opens a blank all white screen & nothing else. The Hubshare logo sits at the top of the page tab?"

Has this been mentioned before, is there anything that I can suggest to this user. I have no access to apple devices and can't test this.

I suggested the normal things such as clearing the cache which he has done.

Any ideas?

Irene