Problems adding new lutron caseta dimmer - eviltoast

Getting frustrated with Lutron’s documentation and links to non-existing pages. I’be got lots of Caseta stuff in the house already but this new summer just won’t go with the flow. Switch and lights work fine. Wireless signal strong. I’ve even reset the switch. All I get though after the -0-second hold to go through the pairing process, is a slow-blinking top led. None of the support stuff covers this example.

I will say that this is the first switch to get installed on the second floor, and the hub is in the basement. Is it too far away? Is that a thing still (not sure if thread and all that is in play here.)

Thanks for the help.