From Github issue: https://github.com/conan-io/conan/issues/5563#issuecomment-527855621
For existing repository, when asked for server capabilities, Artifactory returns the list ['complex_search', 'checksum_deploy', 'revisions']. If the repository doesn't exist it returns ['complex_search', 'checksum_deploy', 'revisions', 'only_vs']. The value only_v2 is quite important because it tells Conan client that only API v2 endpoints methods are available.
The problem is that the error that the Conan client can report to the user has nothing to do with the actual error. Conan client will tell the user to switch to v2, but the problem is in the repo URL.