Is it normal to be asked for an advance fee on a withdrawal?

I was approached out of the blue being told that I was supposed to receive a sudden windfall, someone opened an automatic trading account in my name, or offered to invest in a lucrative mining contract. A while later, I'm being told that there are now "thousands of dollars" waiting to be claimed by me.

However, when I try to withdraw the money, the operator asks me for an "advance fee" or an "unlocking fee" so that they can pay me out my money.

That sounds fishy, what is going on? What should I do?

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Never pay to receive a withdrawal. If they wanted to send you money, they could deduct the fees from the sum they claim you own in your account.

It's a common scam to be asked for money so that you withdraw your funds. In fact, if you pay, they'll find a different excuse and ask you again to pay them, while you in reality never had any money on their website.

Your account balance might show $10k, $100k, $100m but don't be fooled by their values displayed on their website. Never ever pay to withdraw any bitcoins.

Seek help from your local authorities.