Your POE injector is likely (recognized as) an 802.3af (15.4W) injector. Those basic injectors do not have enough power for an AP-535.
Perhaps you are reusing a Ubiquiti injector? Thos may have more power, but often do not comply with the POE standards and will not be identified as an 802.3at (30W, class 4) injector.
Your switch seems to deliver 30W of power and comply with 802.3at. Strictly speaking, for unrestricted operation, the AP-535 can in some cases need even more than that, but in general it should be enough for the AP to operate without restrictions. In some software version, we did turn the system LED amber to indicate this state, but that was later changed (green LED) since the restrictions are minimal (USB port disabled, second ethernet disabled).
You could try to upgrade the code to fix the LED, but the functional behavior should be the same. Or you could enable the IPM feature to remove any default restrictions (and turn the LED green as well).
How did you conclude that the 5GHz radio is not active? Unless not configured or disabled, or if the country setting does not allow 5GHz operation, it should be operational.
------------------------------
Onno Harms
------------------------------