I ran into this issue today, and luckily I have the solution (at least for the issue I was having).
All the packs were offline (other than the one's initially included with Technic), tried Malwarebytes, no malware detected, no firewall or antivirus installed, Windows 7
All I had to do was open Firefox (my web browser), and clear the Cache which was at its maximum capacity (350mb).
(Options -> Advanced -> Network -> Clear Now)
I'm sure it would be the same solution if you used Chrome (clear cache in Chrome) or Internet Explorer (Not even sure how to in that one, because I simply never ever use it).
Hope this helps!
