Hi @Kieran Haycock ,
Thanks for reaching out.
I can understand you are trying to authenticate the users and acquire an access token using Micrsoft Entra ID and getting error due to endpoints.
For supported account type "Accounts in any organizational directory (Any Microsoft Entra ID tenant - Multitenant) and personal Microsoft accounts (e.g. Skype, Xbox)", the endpoint should be https://login.microsoftonline.com/**common**/oauth2/v2.0/token.
The endpoint you are trying https://login.microsoftonline.com/<tenantid> allow users to authenticate from that particular tenant.
However, to authenticate users from other organizations and personal accounts, endpoint must be changed from <tenantId> to common.
Regarding https://<tenantid>.ciamlogin.com/<tenantid>, these endpoints require for consumer account while using Entra External ID for customers when users are registered in CIAM tenant which is different from Microsoft Entra ID.
Hope this will help.
Thanks,
Shweta
Please remember to "Accept Answer" if answer helped you.