Since the re-send can't be found on block explorers it could mean that your original transaction didn't have RBF enabled and nodes still have it in their mempool. This will result in the new transaction getting rejected because it conflicts with the original.
I think that is the case. I read on the forum on the exchange that it does not support RBF.
Your best option is to connect to an Electrum server that is able to see the original and use CPFP to bump the fee.
That's what I will do.
That local transaction is saved in your wallet file but not in all bitcoin nodes, if you want to keep a backup of it;
you either create a backup of wallet or create a backup the transaction by opening it (RClick->Details) and use the "Share" options (via "save to file" recommended).
Thank you. I did not know. I backed up the local transaction file.
I am now waiting for a response on the forum of the exchange. Earlier, I had resynced the SPV file of the decentralized exchange to try re-sending (in vain). But now, the interface of the exchange still has that re-send transaction pending. I imagine I have to restore the backup folder of the decentralized exchange I made before resyncing the SPV file, but I am not sure. I am thinking I want to clarify the exchange part before I return to Electrum to broadcast and CPFP the 'Local' transaction.