The whole problem starts when I play a server(back then it is still normal). I experienced weird lag and I close the launcher. When I reopen again, I discover that I cannot play online, and cannot connect to any server. Then I log out and I cannot login to Minecraft again. It keeps saying this:
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Sorry, but we couldn't connect to our servers.
Please make sure that you are online and that Minecraft is not blocked.
(Certificateexception: No subject alternative DNS name matching authserver.mojang.com found)
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I tried to reinstall the whole minecraft, java, disabled an anti-virus program called 'Webroot', closed defender, firewall, and I am 100% sure that I am online. It does not work.