1 of the 2 update keys won’t work.

Hello I’ve two different websites with two purchased serials. Only one update key seems to work. I can’t update WC Multi Currency to the latest version for my 25lmtd.com website.

I see that both serials are used for the same website ‘imaginaryrealism.com’?

To update the other website (25lmt.com) I thought that I can simply ‘copy and paste’ the update key to WP dashboard > Multi Currency > Update > Auto Update Key.
But this doesn’t work.