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It looks like you restored your site on top of an existing one and that the existing site had a very old version of Joomla namely Joomla 3.7 or earlier. 

As noted in our documentation:

Do not try to overwrite one Joomla! version family with a different one. Overwriting a major version with another (e.g. restoring a backup taken on Joomla! 3.7 on top of a site running Joomla! 2.5 or vice versa) or between different minor versions (e.g. restoring a backup taken on Joomla! 3.7 on top of a site running Joomla! 3.6 or vice versa) will NOT work. Joomla! moves files around between minor and major versions. Since the backup does not delete files not present in the backup archive this will end up with Joomla! being "confused" and malfunctioning. In these cases you should delete the existing files and folders (except, perhaps, user generated content) before restoring the backup. You can safely restore a sub-minor (path-level) version on top of another. For example, you can safely restore a Joomla! 3.7.5 site on top of a Joomla! 3.7.3 site or vice versa.

You need to first delete the following folders from your main site: plugins, includes, libraries, language, cli, components, layouts, administrator, templates, modules (these are the folders Joomla can store .php files and translations, the files which can get mixed up between versions). Then restore your backup again.