Unable to connect to some servers

[#1]

I play counter-strike:global offensive and I am unable to connect to some community servers. I either get stuck on a blank screen or I get stuck on the sending client info phase. Despite this, it tells me in the game console that I've connected to the server even though I never spawn into the level. I get the same issue when watching YouTube videos, some will load and buffer instantly while others will just about manage 144p and will stutter like crazy.

[#2]

Hi Jack97,
I've just been running some diagnostic checks which don't show any obvious issues with the service.
With that in mind I'd get some speed tests run as the next step.
If you can do one whilst connected over WiFi and one over ethernet that would be helpful.