I have exactly the same problem. I have only ever had problems with Owncloud repositories in the 10 years plus that I have been using it on Linux. Why is this? I always install as per the instructions on opensuse, yet I always get problems like this at some stage down the line.
Please Owncloud sort this out once and for all. It’s the only thing letting this product down.
if there are problems with the ownCloud repositories some one of ownCloud needs to get active then i think you could create an issue at https://github.com/owncloud/client/issues
I’m always recommending to open an issue at the github bugtrackers because i’m not sure if the ownCloud people will notice this topic.