Occasionally, transfer-ins to Sav will fail due to an incorrect authorization code from your previous registrar. When requesting a new authorization code from your previous registrar, they may insist that the original code is correct - even if it is not working.
The problem is that the authorization code from the previous registrar has fallen out of sync with the registry. This means you will need to contact the previous registrar and ask for a brand new authorization code, which syncs the codes.
Once they give you a brand new authorization code, log back into your Sav account and update the authorization code in the Transfers page.
If your previous registrar insists there is not a problem with the authorization code and refuse to generate a new one for you, you may need to request escalation in order to get to a technician who can do it for you.