The Ray R6A-C Aps have a higher power output requirement - 18 W minimum upto 30 W
By default Cisco switches only give the output at around 15 W until negotiated via CDP .
Since its a proprietary Cisco protocol , we are not able to negotiate the same.
In such cases, its better to give fixed power on each port of cisco switch
It would help to follow this guide : https://www.thinlabs.com/faq/configure-cisco-switch-for-powering-poe-client
In the above link, we have to use "STATIC" power output of 30 W.