Constant "Matchmaking failed" notifications on my computer.

I have been experiencing this problem recently. Whenever I try to start games on my computer, I receive these notifications stating "Matchmaking failed. Please wait a few seconds and try again." I tried methods, like clearing my browser cache and cookies, restarting my computer, switching to incognito/private mode, switching browsers, and I receive the same exact notification every time I try to start a game. I played on mobile and turned data usage off, and I was able to play on mobile, indicating that there was no problem with my internet. Also, my computer has been really slow lately, and I'm suspicious of a possible virus causing serious issues. Can anyone help me find out why this is happening based off the information above? Thanks for your attention.

Note: This problem does not happen when I'm playing on mobile. 

It happens when it says that I'm connected, but it often says I'm often disconnected.

Same thing has been happening to me today.

oh yeah try reconnecting your network

doesn't work