Solidminer.io, which claims to be a Bitcoin Mining Rig, will allow you to withdraw with the free plan, which will make you think that the website is legit and invest there. But, after you upgrade your plan, you will first of all mine normally and your withdrawal will be processed instantly. But, after a week, they will slow your mining speed and also block your withdrawal, which means, you will never ever be able to withdraw again because the admin will not pay you back. And, if you try to contact them, they will not respond. It's a new strategy that many Bitcoin mining site use to steal people BTC (at the first time we pay you to give you an impression that our site is legit, but after you will never be paid anymore)