[Solved] Android 11 and Firefox: This is how it works for me

I had the problem that I could not install the certificate on my Firefox on Android 11. After a long search, I found this solution that works for me and might also interest you. My environment is in German, so I describe everything in German. If someone knows the exact terms in English OS, please add.

1. download the certificate from the mobile phone on the E-Blocker Dashboard.
2. add the certificate in Android
   1. "Einstellungen" -> "Sicherheit" -> "Verschlüsselung und Anmeldedaten" -> "Ein Zertifikat installieren" -> "CA Zertifikat". Now select the certificate.
   2. "Einstellungen" -> "Sicherheit" -> "Verschlüsselung und Anmeldedaten" -> "Ein Zertifikat installieren" -> "WLAN-Zertifikat" Now select the certificate. Enter a name for the certificate
3. activate certificates in Firefox
   1. Open Firefox -> "Einstellungen" -> "Über Firefox" -> Now tap the Firefox logo five times. Go back exactly one step. -> "Secret Settings" -> "Use third party CA certificates".

I don't know how good this solution is. At least it works for me now.

I hope it helps one or the other