Problem is: it's already spent by either you or someone else that knows your SEED.
Go to the history tab and look for the latest outgoing transaction, check the info and look for the transaction ID (
top).
If must the the one TryNinja had posted: e42672102f676f6b02aa2c888de00cb5e7f4759797d318515508f8c159fadd3e.
Now, try to remember if you made that particular "
send-out" transaction.
If not, your wallet was compromised by either leaked SEED, hacked PC or fake Electrum.
Electrum must only be downloaded from
electrum.org, your SEED should not be stored in any vulnerable environment (
ex. online/local txt file).