Recordings Endpoint in Sandbox Returns Maintenance Page (503 Error)

I'm successfully obtaining a JWT token from:

https://sandbox.openrainbow.com/api/rainbow/authentication/v1.0/login

Here you can see the beggining of the response I get:

{
  "token": "eyJ***J-g",
  "loggedInUser": {
    "outOfOffice": {
      "active": false,
      "message": ""
    },
    ...   

However, when I try to fetch recordings using the following endpoint:

https://sandbox.openrainbow.com/api/rainbow/rvcpprovisioning/v1.0/recordings?limit=100&offset=0&sortField=date&companyIds=67e***507

I receive a 503 Service Unavailable response along with a stylized webpage stating "Site in maintenance" in multiple languages, like this:

        <div class="l" lang="en">
            <p class="p1">Site in maintenance</p>
            <p class="p2">The site is temporary unavailable.<br />
            We are currently performing maintenance.<br />
            We apologize for any inconvenience.
            </p>
        </div>

My question is:
Is this message legitimate? Is the sandbox environment currently under maintenance?
Should I expect the API to work again if I simply wait a couple of days?

Thanks in advance for any clarification.