TiAM0

Having the same issue: java.lang.RuntimeException: Client not authenticated! 403: Forbidden at proxy.auth.ClientAuthenticator.makeRequest(ClientAuthenticator.java:65) at proxy.EncryptionManager.lambda$sendReplacementEncryptionConfirmation$11(EncryptionManager.java:299) at proxy.EncryptionManager.disconnectOnError(EncryptionManager.java:114) at proxy.EncryptionManager.sendReplacementEncryptionConfirmation(EncryptionManager.java:299) at proxy.EncryptionManager.lambda$setClientEncryptionConfirmation$5(EncryptionManager.java:214) at proxy.EncryptionManager.attempt(EncryptionManager.java:101) at proxy.EncryptionManager.setClientEncryptionConfirmation(EncryptionManager.java:203) at packets.handler.ServerBoundLoginPacketHandler.lambda$new$1(ServerBoundLoginPacketHandler.java:27) at packets.handler.PacketHandler.handle(PacketHandler.java:57) at packets.DataReader.readPackets(DataReader.java:163)...

Tried it without the mods and world-downloader works fine. So seems to be an issue with the mods and world-downloader not working together. Upgraded to latest mods including fabric loader...

Thanks for the info. Figured it out, never tried the GUI before, only ever started it in cmdline and didn't see the options for it there or in docs.