It depends entirely on whether player funds were held separately from company money. Under a strong licence with segregated accounts you are usually paid out; under a weak licence with no segregation requirement, you may lose the balance.
Segregation is the whole answer
Regulators classify player fund protection by whether the operator must keep your balance in a separate account from its own working capital, and whether that account is legally shielded if the company fails.
The UK Gambling Commission requires operators to state their protection level publicly and rates it as high, medium or basic. High means funds are in a trust or insured arrangement designed to survive insolvency. Basic means funds are segregated but not protected in insolvency, which is to say you become a creditor like everyone else.
Swedish, Danish and Dutch licences all impose segregation requirements. Lower-tier licences frequently do not, which is the practical difference behind our licence weighting.
What usually happens in practice
Licence revoked, company solvent. You are told to withdraw within a window. Do it immediately rather than waiting.
Licence revoked, company insolvent. With high protection, an administrator pays player balances from the protected account. With basic or no protection, you join the creditor queue and typically recover little or nothing.
Licence expired and not renewed. Usually orderly. The operator stops taking new deposits and processes withdrawals.
What to do if you see the signs
Delays that were not there before, support going quiet, or a regulator publishing an enforcement action against your operator. Withdraw first and ask questions afterwards. A balance sitting at an operator in trouble is the one thing you can still control.
The preventive version
Do not keep a large balance at any operator. Withdraw winnings rather than leaving them as a float. This is dull advice and it is the advice that actually protects money.