Sign-up not working for Subdirectory website using Learnpress v4.1.6

Dear LearnPress Support,

Today I set up a WordPress website on a subdirectory with LearnPress plugin version 4.1.6 installed. However, the sign-up/course enrollment for new account does not work. After some testings, I discovered that LearnPress version 4.1.6 works on website in the root directory and not website setup in the subdirectory.

I have an old website set up in a subdirectory using version 4.1.5. It has been working well for pass years and when I do an update now to version 4.1.6, the sign up fails.

Hope you can look into this.

Regards
Esther