Flow control block folder nav

I try to apply a strict strategyu to block some files extension to upload on my nextcloud.

For example user can only send files with .zip

I try to apply a flow strategy like documentation : /^application\/(zip|x-zip-compressed)$/i

So I doing that: If Type MIME of file is not MIUME perso : /^application/(zip|x-zip-compressed)$/i Block

If I do that, I can’t navigate in my folder. Someone can help me to understand why ?

Thank you