So yesterday I made a transaction after it was broadcasted I close my electrum, a minute later this notification pop up
I sometimes get that error while closing Electrum, and AFAIK it's quite common in Windows.
For your transaction(s), don't worry about them, it's broadcasted in the network via the server where you're connected to
and the network will do the rest, your Electrum is just a client to "
view what's happening" aside from create, sign, broadcast transactions.