it means the maximum amount of ignations attempt have been made and the system has went into lockdown mode
After calling Rheem customer service, I was told I must replace the entire control unit which controls the igniter.
I agree with @tyson, some ignighters are powered and have something that look like a coil around an insulator. Some look like a flat black plate with lines cut through them and the last is a pilot , all of these can fail with a dirty burner or a bad thermocouple safety. A pro may be needed but if you read up on these types of ignition sources you may be able to DIY and save a bunch.