Couldn't verify username because servers are unavailable

[.Fellurion]

have a problem with our server use the modpack ATM 8 and have an auth. but the problem is not my client because i can join other servers with the modpack have already tried a lot, e.g. to delete the user cache here is an excerpt of the error that comes up when you try to join:

 

[08:08:53] [User Authenticator #3/ERROR] [minecraft/ServerLoginPacketListenerImpl]: Couldn't verify username because servers are unavailable
[08:08:54] [Server thread/INFO] [minecraft/ServerLoginPacketListenerImpl]: com.mojang.authlib.GameProfile@54158715[id=<null>,name=_Tauriel,properties={},legacy=false] (/87.123.245.25:5426) lost connection: Authentication servers are down. Please try again later, sorry!
[08:08:55] [Server thread/INFO] [ne.mi.co.AdvancementLoadFix/]: Using new advancement loading for net.minecraft.server.PlayerAdvancements@3b460360
[08:08:55] [Server thread/INFO] [ne.mi.co.AdvancementLoadFix/]: Using new advancement loading for net.minecraft.server.PlayerAdvancements@3f469567
[08:09:00] [Server thread/INFO] [ne.mi.co.AdvancementLoadFix/]: Using new advancement loading for net.minecraft.server.PlayerAdvancements@3e74ed55
[08:09:04] [Server thread/INFO] [ne.mi.co.AdvancementLoadFix/]: Using new advancement loading for net.minecraft.server.PlayerAdvancements@b935490
[08:09:26] [Server thread/WARN] [minecraft/MinecraftServer]: Can't keep up! Is the server overloaded? Running 32708ms or 654 ticks behind
[08:09:35] [User Authenticator #4/INFO] [minecraft/ServerLoginPacketListenerImpl]: Disconnecting com.mojang.authlib.GameProfile@5637f860[id=<null>,name=Tank_1298,properties={},legacy=false] (/xxx): Authentication servers are down. Please try again later, sorry!
[08:09:35] [User Authenticator #4/ERROR] [minecraft/ServerLoginPacketListenerImpl]: Couldn't verify username because servers are unavailable
[08:09:35] [Server thread/INFO] [minecraft/ServerLoginPacketListenerImpl]: com.mojang.authlib.GameProfile@5637f860[id=<null>,name=Tank_1298,properties={},legacy=false] (/xxx) lost connection: Authentication servers are down. Please try again later, sorry!
[08:09:50] [Server thread/WARN] [minecraft/MinecraftServer]: Can't keep up! Is the server overloaded? Running 9417ms or 188 ticks behind
[08:09:56] [User Authenticator #5/INFO] [minecraft/ServerLoginPacketListenerImpl]: Disconnecting com.mojang.authlib.GameProfile@2c6b45e2[id=<null>,name=Tank_1298,properties={},legacy=false] (/xxx): Authentication servers are down. Please try again later, sorry!
[08:09:56] [User Authenticator #5/ERROR] [minecraft/ServerLoginPacketListenerImpl]: Couldn't verify username because servers are unavailable
[08:09:56] [Server thread/INFO] [minecraft/ServerLoginPacketListenerImpl]: com.mojang.authlib.GameProfile@2c6b45e2[id=<null>,name=Tank_1298,properties={},legacy=false] (/xxx) lost connection: Authentication servers are down. Please try again later, sorry!

 

 

but new players can join and have no problems only players with allready existing player stats