The Social Login application doesn't work on XWiki 10 and 11.
The reason seems to be that XWiki doesn't think a dependency of a dependency of the social login application is valid.
More specifically, XWiki doesn't think the JSON (org.json:json:20090211) dependency of the socialauth dependency is valid and it states that it's "Incompatible with provided version 1.8". However, versions of org.json:json are date-like (e.g. 20090211) and not "major.minor" version.
It seems that XWiki is confusing that dependency with the "com.tdunning:json" dependency (which is version 1.8).
This issue doesn't occur on XWiki 9.