Question about REF port of Blackmagic Decklink SDI 4K card

Hello everyone.
I have a question that needs everyone's help. The Ref signal has been received on the card but it says locked. Has this status received the synchronous signal?
If not, what should I do to open the REF Port on the card.
Thank you admin team.
I have a question that needs everyone's help. The Ref signal has been received on the card but it says locked. Has this status received the synchronous signal?
If not, what should I do to open the REF Port on the card.
Thank you admin team.