I see this warning in Hashflare.io panel
Dear users,
Creating new Bitcoin withdrawal requests is temporarily disabled due to a very large number of not broadcasted and/or unconfirmed transactions still pending on the side our provider, block.io. Read more from our newsletter here.
Update 20.12.2017 12:00 UTC: Bitcoin withdrawals are enabled in test mode, with the minimum withdrawal amount set to 0.2 BTC.
Update 21.12.2017 15:30 UTC: We are working on restoring BTC withdrawals for all customers with a lower minimum amount. Unfortunately, the Bitcoin network is still overloaded with unconfirmed transactions. The network fee has risen from 0.0009 to 0.0023 BTC within just a few days and is now reaching up to 0.018 BTC, which means that transactions with a relatively high fee that were broadcasted to the network in the past may now be at a lower priority to be included in blocks, i.e. to be confirmed. Because of the fluctuation of the Bitcoin network fee, the commission fee in HashFlare.io will be changing from time to time.
HashFlare.io is currently working on changing the method of creating transactions in batches (of multiple withdrawals), to reduce the time it takes withdrawals to reach the destination wallets. There is no estimation at the moment.
The insane rise in Bitcoins price has prompted a massive incentive for people to SELL. Because of this, there are far more transactions than the mining infrastructure can handle.
This is the beginning of Bitcoin's scalability failure.
Unfortunately, the possible solutions are;