Android app not asking for certificate

Hi, I am having this error in nextcloud android app stating “SSL initialization failed”. I have made my own certificate and made certificate athentication on for added security. But the problem is that even when I added the certificate to my android phone it works fine for the web. But for the nextcloud app it does not seem to ask for the certificate. Please help.

Here is my apache2 config:

https://pastebin.com/MHRywxR0