Filed to log in authentication servers are unreachable when joining friends server with mods

[Bibbabash]

When i try to join my friends server with mods it just says failed to log in: the authentication servers are currently not reachable. I've been having this issue for a while now and no method I've tried to fix it works. I've seen a lot of people fixing it by modifying the host.txt file and removing anything related to Mojang but when I open mine there's nothing related to Mojang there. I also tried flushing DNS cache, and changing my IPV6 to 8888, but nothing works. 

It only happens when the mods are on too. When I join my friends server on vanilla it works, but not with mods. I can join multiplayer servers like hypixel. I can also play singleplayer with the mods and it works perfectly. The mods are up to date with the versions and the servers, but it just never gets past "Logging in" when i try to join their server. I use Curseforge to launch my mods, so that could maybe have something to do with it because it's technically a third party server, but it hasn't given me any trouble besides this one issue. I do not have MCLeaks and don't know what that is, but how can i search for it anyway to make sure? I have uninstalled minecraft launcher, updated my microsoft and my videocard drivers, reset my wifi and checked my parental settings (I am the owner on my computer), flushed my dns, modifying my host file to delete mojang but there's nothing with mojang on there, disabled my firewall, changed my IPV6 domain to 8888, restarted my router, and none of that works. I have researched this issue thoroughly and tried every solution I have came across and nothing is fixing the problem so i have come here as a last ditch effort. All i want to do is play mods with my friend. My friend has no issues with the server or mods and he has it through curseforge too. I would like further assistance in any way you think could help or even refer me to another forum that could help with this. Genuinely I cannot figure out why it doesn't work I would love any sort of further help.