Got it! Had to go to the settings and remove all active sessions, then I was able to. Definitely a confusing flow...
Discussion
Was about to tell you that. x)
Element's security and session settings are ordered and split weirdly. Recommendation: When you open the Security settings, read it from bottom to top; it starts to make a little more sense which keys go where and do what.
When in doubt, force-logout another device and log back in and do the verification dance again. Usually the fastest solution to things but not the most obvious...