Adobe Lightroom connecting to the server issue

One of the problems I had some time ago with Lightroom (cloud based) recently reappeared. The problem vanished some time ago but now since around few weeks it is back

Namely I am experiencing very, very slow loading time for the previews, assigning keywords, exporting, … Its is so slow that I have to wait for 10 seconds for one image to appear. The reason for that I have discovered is the error “Unable to connect to network”. My internet connections is very good, I have not changed any network configurations. When I put cursor to the cloud icon and wait for several seconds then connection will be reestablished and i can do some operations. However when I start editing the connection drops again and all slows down. 

I have completely resinstalled Lightroom CC, deleted the whole library and redownloaded everything. When I reinstalled the whole operating system then for some time all worked well and out of the blue it stopped again. 

Please could you advise what to do?