Problems with login and/or update after SSL setup

Hello,
I have a Bananapi with Debian and owncloud installed on Apache2.
So far everything has worked fine, but I’ve always accessed via HTTP.
To make the server more secure, I installed an OpenSSL the day before yesterday. Works quite well so far…
I can also still access the login page via http. However, unfortunately I cannot log in. it tells me it took me too long to login… but it worked before?

Furthermore, and much more importantly, I have the problem that after successfully logging in via HTTPS, I can no longer start the latest update (10.10.3 → 10.11) via the owncloud updater. Error: cURL error 60: SSL certificate problem: unable to get local issuer certificate

Can anyone help me with these problems? or first tell me what information you need for further help?

Many Thanks !!!
Warm greetings

can someone tell me, what i may be have changed?
can i temporary disable the ssl certificate?

Why would you like to still login over HTTP when having SSL certs in place? You should rather redirect all HTTP traffic to HTTPS. About the online updater, not sure but I would recommend you to upgrade your oC server by using the manual procedure.