I wanted to submit ai template in zip but why it's showing error

Template files can't be uploaded by “normal” contributors.

You can't submit a template (AIT file). It is an invitation-only program. Details https://helpx.adobe.com/uk/stock/contributor/help/design-template-requirements.html

Show what files are inside the ZIP file. There should be only 2 files:

- the .ai file

- the JPEG file

You may also try a different browser or the FTP option using FileZilla or equivalent. We had reports from users having difficulties with ZIP files and FTP upload worked fine.

https://helpx.adobe.com/stock/contributor/help/uploading-content.html