Around this time yesterday, even the Free BTC transaction accelerator wasn't helping. They had 98 slots left for the hour, but whenever I would try to push the transaction for OP. A notification would pop up saying that the fee rate in the transaction was way too low.
ViaBTC doesn't accelerate transactions paying fee of less than 10 sat/byte freely and that's why you couldn't submit that transaction.
To accelerate such transactions, you have to use their paid service.