Buck-Boost IN LED Green; OUT LED blank

I previously received excellent support troubleshooting a Victron Buck-Boost 50A DC/DC charger for a 12v LFP battery bank. Now that I have it all set up, the converter OUT LED never comes on. The IN LED is green, indicating everything is good on the input side. But the OUT LED winks out after the initial flashing during the startup interval. I don't see any troubleshooting material to explain this condition and would be grateful for forum input.
Thanks!