Encourage the developer to clear their browser's cache and cookies, as cached data can sometimes interfere with login processes.
Azure might have location-based access restrictions in place, which could be causing login issues. Confirm that the developer's Azure account is not subject to specific geographic restrictions or policies that prevent access from outside the US.
Check the status of Azure services by visiting the Azure status page (status.azure.com). Sometimes, Microsoft Azure experiences service outages or issues that can affect login.
If none of the above solutions work, the developer should contact Azure support for assistance.