whenever i go to load onto a minecraft server i always get the same thing saying that it cant connect to the authentication servers. its been like this for months and i do now know what to do

Unable to start LAN server detection: No route to host: no further information:
this text above is the issue that is popping up in the logs as well and ive tried everything that i can think of. letting it through the firewall and stuff and i just cant figure it out. if anyone has any ideas or fixes please let me know and if you need more info let me know what you need.