I assume your redis server is running and you can reach it on the server with e.g.
redis-cli -h localhost monitor
“Exception”:“OCP\App\AppNotFoundException”,“Message”:" does not exist"
From the distance it looks to me that one or more of your apps are broken (assumption).
I’d suggest to disable all apps but some basic ones. For this you will have to connect to your database and run the following statement:
UPDATE oc_appconfig SET configvalue="no" WHERE appid NOT IN ('activity', 'dav', 'files', 'files_external', 'files_sharing', 'files_trashbin', 'files_versions', 'market') AND configkey='enabled';
This might revive your installation.
You then wil have to re-enable the apps that were not in the above list.
Also make sure that there are only ownCloud apps in the directories apps and apps-external. Superfluous directories might break your installation too.