Note: After within a more than half an hour I was able to bump the fees. My transaction got successfully confirmed (paid fees in twice). But this is the first time issue with while using electrum.
What was the reason behind it .This sometimes happens in Electrum because it doesn't check all of the children transactions of the transaction that you will be replacing (
rbf) when recommending the new fee rate.
Example: if the recipient already broadcasted a transaction that spent that unconfirmed transaction's output,
its absolute fee should be included to your replacement transaction on top of the required additional 1sat/vB in the bump txn.
Since you've set double this time, that might have set enough additional fee to cover both of those requirements to bump your transaction.
Take note that in that case, the recipient's transaction that spent your replaced transaction's output have been dropped from mempools.
You might want to inform him about it in case he noticed some discrepancy in his transaction list.
Another possible reason is if your selected server's "
minrelaytxfee" is set to a high non-default value,
That will affect the minimum additional fee that you need to add to your "
bump" transaction.
In this case, changing the server should work.