- πΊπΈUnited States loopy1492
It is still possible to get this error from time to time. In our case, it was because one of the many strange updates to Lightning Media did not get captured in config at some point.
MEDIA: The source field definition for the Remote video media type is missing.
Sadly, the real solution as far as I can tell is to hunt down the config file for the media type and find the source field definition for it. So, for our specific case, I had to hunt down media.type.remote_video.yml and look for the source_configration.source_field in there. Fortunately, it wasn't blank and saw that it was field_media_oembed_video.
I then did a files search for field_media_oembed_video. Of course, it wasn't in my default config folder so I had to go find it in the contrib folders. In the docroot/modules/contrib/lightning_media/modules/lightning_media_video/config/optional/ folder, I found both the field and the field storage configs:
config/default/field.field.media.remote_video.field_media_oembed_video.yml
config/default/field.storage.media.field_media_oembed_video.ymlFinding the field storage was easy, but I had to kind of hope that remote_video.field_media_oembed_video would work since just plain field_media_oembed_video did not exist anywhere in the code base, contrib or custom.
I imported the config and the errors disappeared. Previously, the field edit page for that media type was also broken and it is no longer broken.