The three checks
Identity. A government ID, checked against the name on the account. A mismatch is the most common failure, and it is usually caused by a nickname, a middle name or a married name.
Address. A utility bill, bank statement or similar, dated recently. The address must match the one on the account, not the one you are staying at.
Payment method. Confirmation that the card or account used for a purchase belongs to you. This is where shared cards and third-party payments fail.
Why checks loop
A loop is a rejection without a stated criterion. The player resubmits the same document, it is rejected again, and neither side knows why. The remedy is to ask, in writing, which specific criterion failed.
If support cannot name it, the loop is a process problem rather than a document problem. That is a reason to keep the balance small, not to send a fourth photo.
What to do before you deposit
Ask for the document list in writing, then submit verification with the smallest possible balance. If it clears, you know the account can be paid; if it does not, you have lost time rather than money.
Keep the confirmation and the date. If a later redemption is refused for a verification reason, the dated confirmation is your first piece of evidence.
What verification does not do
It does not create a regulator, guarantee a payout, or stop a state from closing the market. It only establishes that the operator knows who you are, which is necessary for a payout and sufficient for nothing else.
For the full sequence, see redemption and KYC and redemption times.