Hi Emanuele Vacca , I would like to suggest you to check and if necessary adjust this following setting in the location: C:\Windows\System32\drivers\etc\hosts

Check if you have the  127.0.0.1 and the external server address  added to the hosts document:

Please let me know if this solved the issue.

Alex J.

Hi Alex Jude , thank you for your answer. For some reason, the issue is now resolved. I suspect it had to do with Parallels and my internet connection; this is the history of events (although probably not all of them are relevant):

- At the beginning, I was using a normal (2.4 GHz) wifi connection, then I created a 5.0 GHz network because I read that they are faster. I am not sure whether the issue appeared at this point.

- Then I decided to try an Ethernet connection. For sure, the issue appeared a few days after I did this.

- Then I decided to change Parallels' network settings from "Shared network" to "Bridged network > Wifi", and to switch back to wifi rather than Ethernet. 

- At this point, the issue was somehow solved. 

This is why I think it had to do with Parallels' network settings. Now, I don't feel comfortable changing any setting at the moment, since GroupShare uploading is now working properly and I am afraid it might stop doing so. What do you think?

Emanuele Vacca thanks for the update, in your situation, yes, this seems to be related to the network settings as an indication of timeout. You can check the internet connection speed and choose the faster one (I usually use www.speedtest.net to test the internet connection speed).

Alex Jude Somehow the issue reappeared... Ideally, I should be able to understand which combination between Mac network setting (2.4 GHz wifi, 5 GHz wifi, Ethernet) and Parallels network settings actually works, but it looks like I am not able to do it.

I have just tried to implement your previous suggestion; I hope it works.

Alex Jude Somehow the issue got solved. Unfortunately, after I tried to implement your suggestion about changing the hosts file, I couldn't even download any GroupShare project, so I had to undo it. Honestly, I am not sure about what caused the issue and how it got solved. For sure, it has to do with Parallels' network settings ("Shared network", "Bridged network") etc. and with my own connection. At the moment, in Parallels, the suggested "Shared network" setting is selected and I am using a wifi connection and it seems to be working well.

Alex Jude Somehow the issue got solved. Unfortunately, after I tried to implement your suggestion about changing the hosts file, I couldn't even download any GroupShare project, so I had to undo it. Honestly, I am not sure about what caused the issue and how it got solved. For sure, it has to do with Parallels' network settings ("Shared network", "Bridged network") etc. and with my own connection. At the moment, in Parallels, the suggested "Shared network" setting is selected and I am using a wifi connection and it seems to be working well.

 Alex Jude Somehow this issue appeared again, although this time I didn't change any settings. This is so ridiculous and frustrating...