Can't Migrate Standard .NET passwords hashed with sha1


I am trying to migrate a user from a .NET project whos password is hashed with the sha1 algorithm.

Here is the JSON I am sending.

  "user_id": "id1",
  "email": "",
  "given_name": "ExampleCo User1",
  "name": "ExampleCoUser201",
  "custom_password_hash": {
    "algorithm": "sha1",
    "hash": {
      "value": "YZxddfit0uzjuxUf9huwthhkAMw="
    "salt": {
      "value": "ux6wp1UbUbHFRbL+fDke+g=="

The request passes and I can see the user in the database, but can’t login with the supposed password.
Any tips on what I am missing?