[pmpro_confirmation] -> Internal Server Error

PMPro was working fine until some time ago, but I noticed today that the page /membership-account/membership-confirmation/ leads to “Internal Server Error”, without any information in debug.log

If I remove the shortcode [pmpro_confirmation] from the page, the page works.

I also don’t use SSL, but I set the option “Force SSL” to “No”.

What could be the problem ? and the solution ?

Thank you !