Microsoft for Startups - Account Linkage is Broken

My startup Revora is enrolled in Microsoft for Startups. On 21 August 2026 my Azure tenant identity was converted from an external personal-account user to an internal user so I could connect GitHub billing. Since then the Founders Hub no longer recognises my membership: signing in as this account asks me to sign up, and the new account says it cannot be used for credits. Our subscription is already on the sponsored offer. I also am not able to use the startups portal correctly. When I click on the ? for support to raise a ticket, i get the error below, and an endless loop to keep logging in. Can anyone please help me with this? I would like to relink my membership.

{
  "sessionId": "13ccb030747748dd9460cff5b38ae728",
  "errors": [
    {
      "errorMessage": "login_required: AADSTS50058: A silent sign-in request was sent but no user is signed in. The cookies used to represent the user's session were not sent in the request to Azure AD. This can happen if the user is using Internet Explorer or Edge, and the web app sending the silent sign-in request is in different IE security zone than the Azure AD endpoint (login.microsoftonline.com). Trace ID: b94c6ec5-77f7-4db1-9af7-83b6fec91c00 Correlation ID: 1a403baa-3faa-45ce-a0d4-0ee2d389c7cd Timestamp: 2026-09-03 19:29:46Z",
      "clientId": "e6694c91-1590-4e35-9bb7-b865c638b9c1",
      "scopes": [
        "959678cf-d004-4c22-82a6-d2ce549a58b8/.default"
      ]
    },
    {
      "errorMessage": "login_required: AADSTS50058: A silent sign-in request was sent but no user is signed in. The cookies used to represent the user's session were not sent in the request to Azure AD. This can happen if the user is using Internet Explorer or Edge, and the web app sending the silent sign-in request is in different IE security zone than the Azure AD endpoint (login.microsoftonline.com). Trace ID: b94c6ec5-77f7-4db1-9af7-83b6fec91c00 Correlation ID: 1a403baa-3faa-45ce-a0d4-0ee2d389c7cd Timestamp: 2026-09-03 19:29:46Z",
      "clientId": "e6694c91-1590-4e35-9bb7-b865c638b9c1",
      "scopes": [
        "959678cf-d004-4c22-82a6-d2ce549a58b8/.default"
      ]
    },
    {
      "errorMessage": "login_required: AADSTS50058: A silent sign-in request was sent but no user is signed in. The cookies used to represent the user's session were not sent in the request to Azure AD. This can happen if the user is using Internet Explorer or Edge, and the web app sending the silent sign-in request is in different IE security zone than the Azure AD endpoint (login.microsoftonline.com). Trace ID: b94c6ec5-77f7-4db1-9af7-83b6fec91c00 Correlation ID: 1a403baa-3faa-45ce-a0d4-0ee2d389c7cd Timestamp: 2026-09-03 19:29:46Z",
      "clientId": "e6694c91-1590-4e35-9bb7-b865c638b9c1",
      "scopes": [
        "959678cf-d004-4c22-82a6-d2ce549a58b8/.default"
      ]
    }
  ]
}