Can I schedule my form to be disabled on a certain date?

Yes, this is possible to do with JotForm, while on the Form Builder you only need to click on the Preferences icon, once there you need to click on Form Limits tab and then set the expiration date, here is an image for further reference: 

Hope this helps. 

Every time I put in a date it says the date is invalid. I have tried several variations of the date and time.
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May I know what is the date and the time your trying to put on the expiration date option?

The invalid error only appears if you put "24:00" as the time. It is not valid because "24:00" is considered as the next day. So instead of "24:00", you should be using "00:00". Please check the animation below: 

Hope that helps. Thank you.

I was using 24:00 so I changed it to 01:01 of the next day and it worked.
Thanks
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Hello CWGSUser,

I am glad to know that your issue is solved.

Do get back to us if you have any questions.

Thank you!