Alexa no longer is finding new divices

hello, first thanks in advance!

I have hub 2.0, alexa, two echo’s (1st 2nd gen) and about 64 device so far connected to my smartthings hub.
I add them a couple a month
(so my wife does not notice an $800 charge on amazon)

I recently added a couple of GE light switches and they are connected and working in smartthings app, but when I go to alexa and ask “discover new devices” or manually do it it in the app it finds nothing.
is there a limit to how many devices she can use? what gives?

any help is appreciated

i rebooted the hub and all 3 amazon echos and still nothing. it refuses to find the 4 new switches i installed recently

ok figured it out, i went to the smartthings app then smartapps, the went in to amazon echo. there you can have echo access to things manually or check off “allow alexa access to all devices” once i checked of that it found 84 devices, wow I though i was only missing 4