ashenlight_

I am trying to play a modded modern minecraft on a server but this message always pops up (Not the screenshot but the exact message) I have followed every instruction I found online be it turning off my ipv6 in control panel, manually setting my DNS server assignment to only use ipv4 in Network & internet, deleting anything related to "Mojang" in C:\Windows\System32\drivers\etc\hosts, troubleshoot my internet, reset my wifi adaptor on my laptop, reset my wifi too I am currently using a modpack called "Craft to exile 2" for anyone knowing a problem with that modpack, do anybody have any idea to fix or try?