there is customer registration page where I follow this url https://blog.chapagain.com.np/magento-2-customer-image-file-upload-in-registration-account-page/ to add file upload field.
It is working fine but the problem is when I upload pdf file name with vendor's licence.pdf and click submit it throws 404 error: Page not found
if I rename file name to vendors licence.pdf then it went through without any error. I do not where I have to look at ? I tried to put die() function in /vendor/magento/module-customer/Controller/Account/createPost controller but no luck. how can I know where is the problem which file cause it? there is no any log. Please help