Then it's a low fees issue, bitcoind on electrum servers is rejecting transaction due to low fees.
Just increase fees and try again or manually create and broadcast transaction but it can take some hours to some days, to get confirmations.
Ps: How big is your bulk transaction? I mean how many addresses?
So the transaction has 2 inputs and 29 outputs. I just now tried with a fee of 0.001 BTC and it still returns the exact same error. How much of a fee do you think would be appropriate?