I'm unable to send btc with electrum, any amount I try gives this error:

error: {u'message': u'TX rejected', u'code': -22}

I have the requested balance & the transaction fee inside my electrum wallet, and also I've tried multiple send-to addresses.

Anyone have a guess what could solve this error?
I'm using the latest osx client, 1.9. It worked for lots of transactions before this error.
Thanks!