Plugin page problem. Best guess is that your server has a bitch of a time communicating with GitHub.com What happens if you go to settings - Notification settings, and disable the OS Update check and plugin update check, and then go to the plugins page?
Docker Apps: Only suggestion to to delete the docker image (Settings - docker - advanced view, disable service, delete the image, re-enable service), and then re-add your apps via Apps tab, previous apps (check off all your apps, then Install Multi)