Is it possible to have sticky header just for one page?

I'm new to this community, hope I'm highly welcome

I watched almost a dozen of YouTube tutorial, and it didn't work. So, here's the problem: I'm not getting the email for the forms submitted in my website. To check the submissions, I have to go via WordPress> Ninja Forms> submissions which is not always practical. Is it because: I'm using shared hosting & someone else with the same IP or whatever is spamming sending thousands of emails. And that's getting me blacklisted as well. Or am I missing on something out?

Greetings to you all am new in this please i need you guys to help me achieve my dreams thank you 🙏

Hi Everyone, Am into Online Business