Can you see any other transactions on the history tab and does Electrum show the correct balance? If yes, then your issue isn't due to a connection problem.

The reason why you can't see the unconfirmed transaction is, most likely, because it has been dropped from the mempool of the server Electrum connects to. You can fix this by trying to connect to different servers (from Network Settings).
However, there is no need for this if your only aim is to accelerate the transaction. Just create a new one and make sure to pay enough fee this time.