Yes, forgot to mention I had to install Android client v0.11 because I am using self-signed certificates (letsencrypt).
I was getting that error when trying to connect :
javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
Issue was already raised here : https://gitlab.com/fmd-foss/fmd-android/-/issues/362