I have tried anything that came into mind: Reset modem, add Minecraft to exception list etc. Now this is the launcher that claims it doesnt need Java, is that true or not? because as far as I know the latest version of Java is on my PC. I can play Minecraft Vanilla just fine with FTB and Technic but Voxelmap needs Liteloader and it claims that Minecraft Vanilla from Technic doesnt have a Launcher Profile so I had to resort to using the official one.
UnknownHostException gives the error:
authserver.mojang.com could not be resolved and thus your PC has no idea how to connect to that server, the DNS server you use simply has no IP for that server.
Try using a different DNS server like Google's Public DNS
220.127.116.11/18.104.22.168 and run
nslookup authserver.mojang.com 22.214.171.124 from CMD to store it to your DNS cache.
The result will be something like:
Unauthorized answer: Name: authserver.mojang.com Address: 126.96.36.199
Chances are you haven't added the correct java to the exception list. When you run the "java-free" installer version of the game, it will install a minimal java runtime in the installation directory, and uses that to run the launcher and the game by default.
This runtime is typically found in
[Installation Directory]\runtime\jre-x64\1.8.0_25. Note that
[Installation Directory] is not your
.minecraft folder, but rather something like
C:\Program Files\Minecraft or whatever you set during the installation.
Make sure to add both
javaw.exe to your firewall's exception list.
Alternatively, you can get the old
Minecraft.exe without the java runtime at https://minecraft.net/download and use that.