“421 Misdirected Request” - Can’t connect to UKNI NMVS


With the deployment of NMVS Core 1.10 to the UKNI NMVS on 2nd June 2022 a security hardening has been implemented to validate the URL of transactions sent to the NMVS. If you are receiving the response “421 Misdirected Request” when you perform any transactions following this release, then your NMVS software either needs upgrading or has a misconfiguration.

All active UKNI NMVS software suppliers have confirmed that their software has been upgraded to meet this security requirement. If you have this error message it is likely that one of two situations exists:

  • The specific system you are using has not received the updated NMVS software
  • The specific system you are using has a local misconfiguration

If you have already received an email from us with the subject “FINAL REMINDER - Action Required for your FMD Software“, we have identified you have a local misconfiguration and that email has the detail you need to fix it.

Otherwise, you will need to contact your NMVS software supplier. You should refer them to our communications to them regarding “UKNI MVS version 1.10 Release - April 2022 - Breaking Changes”.