Revert Domain Name Change

Last night I changed the domain name of one of my sites (a subdomain), and today I realised that was a mistake and I've changed it back to what it was. However I'm finding that the URL is now redirecting to a different subdomain and I need to stop it from doing that, but I can't seem to find where to remove that from Forge. Does anyone have any experience in fixing this kind of situation? Here is the domain in question: https://vehicle.vehiclecheckr.com/ but you'll notice it redirects to admin.vehiclecheckr.com instead.

A consequence of doing this is that I can't get a LetsEncrypt SSL cert for my domain either, here is the error message:

--2019-03-15 00:58:29--  https://forge-certificates.laravel.com/le/511324/404830?env=production
Resolving forge-certificates.laravel.com (forge-certificates.laravel.com)... 104.25.8.32, 104.25.9.32, 2606:4700:20::6819:820, ...
Connecting to forge-certificates.laravel.com (forge-certificates.laravel.com)|104.25.8.32|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: ‘letsencrypt_script1552611509’

     0K ..                                                     33.7M=0s

2019-03-15 00:58:29 (33.7 MB/s) - ‘letsencrypt_script1552611509’ saved [2347]

Cloning into 'letsencrypt1552611509'...
ERROR: Challenge is invalid! (returned: invalid) (result: {
  "type": "http-01",
  "status": "invalid",
  "error": {
    "type": "urn:ietf:params:acme:error:unauthorized",
    "detail": "Invalid response from https://admin.vehiclecheckr.com/.well-known/acme-challenge/2KmgDBT1KHlYfbpjGB56egAcIe9Vgn4uqcslP6MeShQ [2606:4700:30::6812:2ab3]: \"\u003c!DOCTYPE html\u003e\n\u003chtml lang=\\"en\\"\u003e\n\u003chead\u003e\n    \u003cmeta charset=\\"utf-8\\"\u003e\n    \u003cmeta http-equiv=\\"X-UA-Compatible\\" content=\\"IE=edge\\"\u003e\n   \"",
    "status": 403
  },
  "url": "https://acme-v02.api.letsencrypt.org/acme/challenge/qcSpFSsf3bBFUpkrURVVBaYIvCXwnA4-OAdsJXUbLzE/13662255850",
  "token": "2KmgDBT1KHlYfbpjGB56egAcIe9Vgn4uqcslP6MeShQ",
  "validationRecord": [
    {
      "url": "http://vehicle.vehiclecheckr.com/.well-known/acme-challenge/2KmgDBT1KHlYfbpjGB56egAcIe9Vgn4uqcslP6MeShQ",
      "hostname": "vehicle.vehiclecheckr.com",
      "port": "80",
      "addressesResolved": [
        "104.18.43.179",
        "104.18.42.179",
        "2606:4700:30::6812:2ab3",
        "2606:4700:30::6812:2bb3"
      ],
      "addressUsed": "2606:4700:30::6812:2ab3"
    },
    {
      "url": "https://vehicle.vehiclecheckr.com/.well-known/acme-challenge/2KmgDBT1KHlYfbpjGB56egAcIe9Vgn4uqcslP6MeShQ",
      "hostname": "vehicle.vehiclecheckr.com",
      "port": "443",
      "addressesResolved": [
        "104.18.42.179",
        "104.18.43.179",
        "2606:4700:30::6812:2bb3",
        "2606:4700:30::6812:2ab3"
      ],
      "addressUsed": "2606:4700:30::6812:2bb3"
    },
    {
      "url": "https://admin.vehiclecheckr.com/.well-known/acme-challenge/2KmgDBT1KHlYfbpjGB56egAcIe9Vgn4uqcslP6MeShQ",
      "hostname": "admin.vehiclecheckr.com",
      "port": "443",
      "addressesResolved": [
        "104.18.42.179",
        "104.18.43.179",
        "2606:4700:30::6812:2ab3",
        "2606:4700:30::6812:2bb3"
      ],
      "addressUsed": "2606:4700:30::6812:2ab3"
    }
  ]
})

Thank you in advance.