bluetooth connection problem

[Geoffrey Leach]

Bluetooth headphones report that they are connected and paird. The
Bluetooth devices app reports:  Connection failed: device did not
respond.

Fedora 40,  6.9.9-200.fc40.x86_64 kernel, XFCE-4 desktop. Everything
up-to-date.

On the same box, headphones pair with no errors under Unbuto 24.04

I expect that I have a configuration problem, but I have searched in
vain to discover what that might be.  Assistance would be appreciated.