Do you have the GPS sync or non-sync connectorised radio?
The non-sync radio uses the Canopy pin out, which would be +V = 7/8 and return -V = 4/5. You would thus need to reverse the polarity when powering from your standard injector.
The GPS sync variant is 802.3af compliant, so it should work with your standard poinouts, as well as Cambium's Canopy pinout.
I thought the ePMP series automatically senses and works with any of the 24V Passive POE. Since, in essence you can use a Mikrotik, Ubiquiti and/or Canopy PoE brick/ inserter with any of these CPE radios (such as the ePMP Force 180 and up). That way, you didn’t have to enter the customer premises to do a power supply swap.
Not all radios are agnostic. That generality has cost some a few radios before they figured it out. Do not assume and read the manuals and tech docs carefully.
Canopy/cambium passive is +7,8 -4,5
Ubiquity is +4,5 -7,8
Only the GPS syncd radios do 802 3at.
The newer force300-25’s are agnostic but your not guaranteed that your distributor has the new or old ones in stock. So be very careful