The recirculation pump on my spa seems to run, but there is not the flow out of the bottom port as indicated bubbles from the ozonator. When the main pump is on the bubbles come out of this port.

The dc resistance is approximately 56.4 ohms on the pump.

What is the most logical issue pump failure or clogging of the lines?

Tiger River Bengal

Pump Failure -
However, if it actually sounds like it's running, you may want to pull off the suction line and let water run backwards thru it to be sure nothing is clogging the center suction area of the impeller.

Last resort, disassemble the pump and inspect for anything restricting the impeller/rotor.

its possible that your ozone is clogged, mine clogges up every month.

Try removing the filter as well. A dirty filter will stop ozone flow by limiting the volume of water pumped by the circ pump. Also, the ozone check valve may be stuck.

No ozone bubbles doens't usually mean circ pump failure, though when it fails it won't bubble. If the spa is maintaining heat, the circ is is still operating.