Your dishwasher model uses a separate, electrically driven pump (see the following link) just to drain the water. Is that pump running or at least getting power when it should be draining?
LINK > Frigidaire FDB510LCS0 Dishwasher Drain Pump
Power to it but NO drain = pump problem or drain hose/plumbing/internal pump obstruction. No power to it would have to be traced to determine where the stoppage is. It might be caused by a problem in the dishwasher's control or the wiring between it and the pump.
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