Sorry you are facing this issue, it would be my pleasure to help you.
Welcome to the Shopify community!
Thanks for your good question.
Please share your site URL,
I will check out the issue and provide you a solution here.
thanks for store url but sorry its passwords protect
can you please check your theme setting its allow to popup modication option
did you check customization option on your theme?
can you please share your theme zip file so i will check and let you know