I need your help with Putty

Hi
I'm using ec2 but I have a problem today.
It's about 'Network error: Software caused connection abort'
I was using it a few hours ago, but now I'm in trouble. What's the problem?
Is the server checking? Or my account a problem?
I didn't touch anything and my 'ec2' works well.
Please, I need your help right now. Give me an answer.