SSL_PROTOCOL_ERROR outside wifi home network


after changing my modem and making all necessary changes, i can still access NC (eg, when i’m connected to internet via my wifi homenetwork but not outside it. In this case i have this issue : net::ERR_SSL_PROTOCOL_ERROR. Any idea about how to fix it?
I have NC 12.0.3 installed on raspberry pi Jessie.

Nextcloud version (eg, 12.0.3):
Operating system and version (raspbian Jessie):
Apache (Apache 2.4.25):
PHP version ( 7):
Is this the first time you’ve seen this error?: yes

Open your Chrome/Firefox developer tools and inspect your SSL certificate, that’ll likely tell you why.

Thanks, but i didn’t find something helpful to me. When i’m on the android app i have “failure of SSL initialisation”…(translated from french)