>If someone can give me some pointers, I'll try to do it, if it's not very complicated and time-consuming.
All of your questions have been asked like 100 times already
and you just need to use the search, and read (always check the top of forums before you post. About each forum here got sticky threads with information for most asked questions!):
a) Use the forum search in the Minion forum and search for "cannot connect" -> You should find plenty of similar posts if users asking the same and what the answers were
b) read the sticky thread named "Troubleshooting guide" at the top of this forum here please
I bet it got to do with either your Minion version -> needs an update
Or with your firewall and antivirus tools
Or with the java ip4 vs ip6 info (command line trick to change that, see sticky troubleshooting guide)
Or you are based in a country where your ISP blocks access to minion, try to reach the cdn website like described in the sticky troubleshooting guide
Or your VPN is blocking minion access
If that still does not help:
c) read the sticky thread named "If posting a bug report..." at the top of this forum here please
And post your Minion.log and xml files as asked for.