Cannot Copy Template

I created a membership app for a sisterhood that has many chapters, the sisterhood has many chapters, not the app (lol).
My chapter loves our ‘Digital Yearbook’.
I created a template, back when Glide was new, it might have been one of the first templates. Actually, David Siegel helped me make the template.
Well, now it’s finally gaining some traction and other chapters are interested in copying the template. So that’s cool.
But they are getting an error that says something like cannot duplicate original authentication - or something like that - It’s like the template is too complicated now.
What should I do to simplify it and make it accessible for others to copy?
The address to the app is
I’d even pay someone to help me streamline this…

You can try clearing all your empty rows and columns to see if people can duplicate it.

How many rows do you have?

I did go through and delete all extra columns to the right and all rows below the data down to the 1000 row.
It has quite a few tabs.

How many sheets do you have in your spreadsheet, and how many tabs do you have in total? If you can decrease the amount of tabs I think that would help as well.