A video of play later in the day does not explain why your dog stops at the entrance. It might be the door, the handoff, noise inside or something that happened there. Do not drag or carry a resisting dog through just because they eventually seem to play.
Pause and ask what the day looks like
Tell the staff exactly what you see at drop-off and ask them to walk you through the arrival, group assignment, rest, supervision and how they handle a dog who wants space. Ask for observations across the whole day, not only a lively clip. Check whether your dog is relaxed at pickup and after returning home. If the reluctance is new or your dog seems sore, ill or unusually distressed, involve your vet.
Until you understand the refusal, arrange another safe care option if needed. Daycare is optional. A dog walker, a quieter setting or time with a familiar sitter may fit better. If the facility and your dog are otherwise a good fit, ask whether they can offer a quiet, voluntary entrance visit without a full day. End it before the dog becomes worried. The staff should be willing to discuss a plan rather than insist you push through the door.
Today, call the facility and describe the exact moment your dog stops. Ask what they observed and whether a no-pressure visit is possible. Their answer matters as much as the next attempt.
Sources: AKC on choosing a daycare and assessing staff and dog fit. VCA on fear of places and refusing to move.