Sounds strange. Was this for all users? When you say you couldn't create a WO, did you get an error? 

Have you recently done any changes in the environment (looking at the other things you've posted recently makes me wonder)? 

Did you get issue only for work order screen? Were you able to work on other windows in this 3 hours? Are you getting any error or just stuck in the window?

it was for work order only and there were no error messages.

Yes, it was for all users and No error were flashed.

So what was the behaviour? New button or save button unresponsive?

So what was the issue you are facing? New button was not active?

I t was giving issue related to database connection but i have not captured the error. But, now troubleshooting the issue.