After submission of NATA 2018 application form Payment gateway page is not appearing.
Same problem happened with me but I don't have solution
What should I do
Please first check your internet connection.I suggest you to wait for an hour or two and if the problem persists then you need to contact the respective authorities for more clarification on this problem.
You can take guidance from the below website to fill NATA application form:
https://engineering.careers360.com/articles/nata-application-form
Good luck.