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 :

In the above link, we have to use "STATIC" power output of 30 W.