Apologies if this has previously been posted.
I have just managed to get Acquisition to connect. I have 2 Macs, 1 would connect and one wouldn't so I knew the issue was machine based rather than router.
Fix:
Apple Menu
System Preferences
Personal > Security
Firewall Tab
Set access for specific services and applications radio button checked
In the list of applications find "java"
The setting for java that has allowed Acquisition to connect for me is "allow incoming connections"
If your setting states "block incoming connections" this can be amended by clicking on this setting (effectively the words) and the other option appears, can be selected and set.
I then opened Acquisition and it connected. I have backtracked on this to test it to make sure that this is actually what has affected the change for me and sure enough if I alter the setting back, Acquisition won't connect.
If this has previously been posted, many apologies and best of luck.