What version of Electrum you currently using?
I tried verifying the sign message in my Electrum 3.3.4 it's working fine without issue.

You might be using a fake Electrum so tell us if where did you download the Electrum installer(It should be downloaded from electrum.org)? and let us know if what OS you are using?

If you are using the orig Electrum try to use the latest version of Electrum and test it again.