A few common reasons:
Name, date of birth, or address mismatch. What you typed doesn't exactly match what's on your ID or in official records. Even a small thing — a hyphen, a middle initial, the apartment number on your address — can trip it up.
Document quality. Blurry photo, glare, cropped corners, or low lighting can make the system unable to read your ID.
Selfie doesn't match the photo on your ID. Different lighting, angle, glasses, hat, or significant time since the ID photo was taken.
Document authenticity flags. Sometimes the system flags an ID for review (this isn't always an accusation — it can happen for legitimate IDs too).
Risk signals on your email, phone, or device. A brand-new email, a VOIP phone number, or a flagged device can cause a verification stop.
To improve your odds on the next attempt:
Type your info exactly as it appears on your ID (including punctuation, suffixes like Jr./Sr., middle name)
Use good lighting, no glare, all four corners visible for ID photos
For selfies: face the camera, no hat or sunglasses, neutral expression
Only the compliance department can give you the specific reason. If you've failed three times and they review your case, they may share more detail when they reach out.