That's been the case for every issue I've had with an Ubisoft game. I fumble with support who just shotguns the issue until I figure it out myself.
Georgia here in the US and couldn't activate after midnight EDT(0500 UTC). The exe file name change suggested above worked perfectly. Thank you!
Apparently the game will launch if you rename ImmortalsFenyxRising_plus.exe to ImmortalsFenyxRising.exe, even if you only have the Ubisoft+ version.
https://www.reddit.com/r/FenyxRising...eb2x&context=3
fixed legend
How utterly ridiculous is it that a normal player once again came up with the solution, instead of actual ubi mods. These people are completely useless. In another thread one said: "GuYs tHe ReLeAse DaTe HaS bEeN kNoWn FoR wEeKs", while not even 2 minutes later someone else posted this solution which actually worked. Embarrassing. Anyway, thank you.