He's using an outdated version of electrum. He won't be able to connect to any server with it. He should upgrade to the latest version.
I guess you probably didn't notice, the OP's question was posted back in 2019. I'm sure he's already upgraded to a newer version of Electrum wallet by now, if he is still using it.
Possibly what Abdussamad responded to was the following Saint-loup post:
https://bitcointalk.org/index.php?topic=5129190.msg60586747#msg60586747, where the notification in his case is the same as in the OP.
Moreover I don't think most of people willingly try to broadcast transactions without working connections.
But it can happen when the internet connection or the server is suddenly disconnected without the user realizing it when they are going to broadcast the transaction.