can't access offline activation for Lightroom 6

i am trying to install a purchased copy of LR6 on mac os mojave.

i successfully installed on my mac, including entering the serial number during activation.

however, upon opening LR, it says i need to connect to the internet to complete online activation.  there is supposed to be a link in that dialog (something like having trouble connecting, etc) that will trigger the offline activation page, but there is no such link.  the only choice is "activate later".

any ideas?

thanks