Are you sure you typed this phrase correctly? "sudo pip3 install".
- you can try to download
https://download.electrum.org/3.1.3/Electrum-3.1.3.tar.gz [using this URL] and run electrum from its root.
If this does not work, try this code
Check and download (update) last electrum version, backup wallet. Linux Only it helped a user on Reddit, I bookmarked GitHub URL, but I think the same Linux OS.