AKradian

Your title and description don't match.
Are you trying to upgrade a Tenebris ring or the Glory Guard: Guardian ring?

Unfortunately it's a case of "cc-dc". The event moves everyone to the same channel, and changing channels often causes people to disconnect within a minute or two after.

I am not seeing anyone else complain about these or similar skills, so I'm going to ask you to try doing a full shutdown of your computer (https://www.howtogeek.com/129021/how-to-do-a-full-shutdown-in-windows-8-without-disabling-hybrid-boot/ - this works for Windows 10 as well. For Windows 7, just do a restart) and see if the problem persists.

The details will be given in the v210 update notes, which should be out no later than the update itself (December 18).

Maple Relay runs for 35 days, of which you only need to complete 20. That is extremely lenient for a Maple event. Usually you can only miss 10% of any event and still get the grand prize. And no matter how much they extend an event, there will always be those who joined the game too late to complete it. That's just how time-limited content works.
If you don't have the required Star Force, you can do the Black Heaven blockbuster. It only requires level 120, and takes a few hours.