By the way, I temporarily deleted your “ultimo-api-fix.php” file in my mu-plugins directory to see if the details in the subscription area would appear again. They’re no longer displayed. That’s not good. I can’t seem to access the overview permanently anymore.
The code I provided from github above, copy and paste it into wp-content/mu-plugins/fix.php and see if the slowness goes away and the subscription panel is restored.
Yea, I think at this point your version is relying on something to do with the API. Do you have any custom Ultimo code, mu-plugins or plugins installed? There might be other code causing issues.
I’m not an expert. There’s just a “hosting.php” file from WPMUDEV in the mu-plugins directory. I haven’t changed anything else. You wrote at the beginning of this post that you have a customer who also has version 1.10.18, and after uploading your file, everything works. Is it possible to get the wp-ultimo 1.10.18 plugin from your customer? Then I could test it. Or what do you suggest?