Internal Exception: java.lang.illegalstateexception: could not determine owner for override on aroma1997sdimension:aromicportal. Vaule: block(null)
When using a dedicated server that has ever had any blocks removed (either by mod update rename/removal) or an entire mod removal from the instance, clients will sometimes encounter the above error when trying to connect to the server. Usually a client restart will fix it, but I've had multiple people report that it can take 4+ consecutive restarts before they can finally load into the SMP world and some are not able to ever get in no matter how many restarts of the client or server.
As directed by LexManos in this PR ( https://github.com/MinecraftForge/MinecraftForge/pull/4266 ) I had a user that was experiencing this add "-Dforge.debugRegistryEntries=true" to their launch args and send me their latest.log as follows: ( http://paste.ubuntu.com/25342196/ ) This example came from 14.21.1.2443 but as far as I'm aware it's been experienced in multiple 1.12 forge versions.
I am an administrator of the "All The Mods" modpack team and have encountered this error with many of our users on our official servers as well as having reports made on other servers. Here's an example of the same error being reported to Aroma1997's issue tracker as well ( https://bitbucket.org/Aroma1997/miningworld/issues/134/people-not-being-able-to-join-server ) demonstrating the issue is widespread.