Skype "Poor Connection" Issues

I need Skype for work, period. It's a deal-breaker if I can't get this to work. I can use skype with my phone hotspot, but not over my wireless panoramic modem. Speed tests all check out, but something on the network is blocking the call or causing lags big enough to drop the call and give the "Poor Connection" error.

Has anyone else experienced this with Cox? How'd you fix the issue? 

Also, what alternatives do I have to COX? I am not under contract.