I was having alot of lag today while playing SK . Tried alot of things to fix it :

1. Restarting Steam
2. Restarting the router
3. Clearing Game Cache ( Not sure if it helps )
4. Restarting the whole computer

After that , I saw some posts that suggest putting Graphics on low ( Which I am using ) and unchecking all other boxes . After I did that , I tried to log in with my Steam Account , but it says the following :

"We experienced a problem authenticating with Steam..."

As before , I tried restarting Steam and clearing game cache but nothing is solved .

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I just want to know if the problem is from Steam or my Internet , and if it's from Steam is all I can do is waiting ?

Note : I can log in with my Non-Steam account normally and without any lag .