django.core.management.base.SystemCheckError: SystemCheckError: System check identified some issues:

ERRORS:
djangocms_file.File.file_src: (fields.E300) Field defines a relation with model 'File', which is either not installed, or is abstract.
djangocms_file.Folder.folder_src: (fields.E300) Field defines a relation with model 'Folder', which is either not installed, or is abstract.
djangocms_picture.Picture.picture: (fields.E300) Field defines a relation with model 'Image', which is either not installed, or is abstract.
djangocms_picture.Picture.thumbnail_options: (fields.E300) Field defines a relation with model 'ThumbnailOption', which is either not installed, or is abstract.
djangocms_video.VideoPlayer.poster: (fields.E300) Field defines a relation with model 'Image', which is either not installed, or is abstract.
djangocms_video.VideoSource.source_file: (fields.E300) Field defines a relation with model 'File', which is either not installed, or is abstract.
djangocms_video.VideoTrack.src: (fields.E300) Field defines a relation with model 'File', which is either not installed, or is abstract.

WARNINGS:
?: (urls.W001) Your URL pattern '^robots\.txt$' uses include with a regex ending with a '$'. Remove the dollar from the regex to avoid problems including URLs.

System check identified 8 issues (0 silenced).