Thomas,
The networking and proxy code in MyEclipse isn’t something we control (this comes from the base Eclipse platform), but to the best of my knowledge, nothing has changed here from 2023.1 to 2024.1.
With 2024, the Java version that MyEclipse uses to run has been updated from 17.0.4 to 17.0.11. Is there a chance you made other changes to the Java binaries (like adding a certificate to it) or did you by any chance have any other proxy/network settings in the myeclipse.ini file? Please see the Proxy Authentication section in this post https://www.genuitec.com/forums/topic/configuring-the-network-proxy-settings/ specifically the switches at the end of the post.
If this doesn’t help, can you please send us your workspace error log? Also, what action are you taking that is resulting in the auth required message (trying to update, running a build, etc.)?
Thanks!