Try entering this at the Electrum import field:
Specifically... you need to use the following steps in Electrum:
- File -> New/Restore
- Give your wallet a name
- Select "Import Bitcoin addresses or private keys"
- in the textbox, enter: p2wpkh-p2sh:YOUR_PRIVATE_KEY_FROM_COINB.IN
- Press Next
- Enter a password if desired
Once the wallet is opened, check the "addresses" tab, (you might need to use "View -> Show Addresses") and see if it has created the "3EKwWuPu979SBfd8sVKfAdneFXMoYMPJoy" address. If it has, it might just take a few moments for Electrum to download the blockchain headers and sync.
Check that the coloured dot in the bottom right corner is either "Blue Arrows" (syncing) or a "Green dot" (connected/synced)... if it is a "Red dot" then you are not connected to a server and it can't sync.