Incorrect API version endpoints
Verified in v2.6.1
The endpoint to API Versions
resource should be /api_versions
and not /api_version
.
See https://www.etsi.org/deliver/etsi_gs/NFV-SOL/001_099/013/02.06.01_60/gs_nfv-sol013v020601p.pdf, section 9.3.2