Address verification emails are extremely slow (was: are not being sent)

Another one here:

{
  "date": "2021-12-14T15:26:35.252Z",
  "type": "sapi",
  "description": "Send an email address verification email",
  "client_id": "GTEm8P6Q5LJUqFsd3sLul8rm0nej9i3o",
  "client_name": "",
  "ip": "35.167.74.121",
  "user_agent": "Chrome 96.0.4664 / Linux 0.0.0",
  "details": {
    "request": {
      "method": "post",
      "path": "/api/v2/jobs/verification-email",
      "query": {},
      "userAgent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36",
      "body": {},
      "channel": "https://manage.auth0.com/",
      "ip": "35.167.74.121",
      "auth": {
      }
    },
    "response": {
      "statusCode": 201,
      "body": {
        "id": "job_556CNvGhXhiN3Ev7",
        "status": "pending",
        "type": "verification_email",
        "created_at": "2021-12-14T15:26:35.216Z"
      }
    }
  },
  "user_id": "google-oauth2|101071305325880252887",
  "log_id": "90020211214152640534080138988823380134702522962144133218",
  "_id": "90020211214152640534080138988823380134702522962144133218",
  "isMobile": false
}

API response:

{
  "type": "verification_email",
  "status": "completed",
  "created_at": "2021-12-14T15:26:35.216Z",
  "id": "job_556CNvGhXhiN3Ev7"
}

No email received.