Hi @جن Jinn Jin ,
This script is used when the same email is registered as Personal as well as Work Account. Easier way to confirm this is by opening a browser in in-private/incognito mode and try to login to Azure Portal. You should get below prompt which is as a result of OldConvergedLogin JavaScript.
Now there can be multiple reasons why the script is failing and might need some deep level of troubleshooting and data gathering to understand this.
However, as a quick fix, you can follow the instructions provided here: https://support.microsoft.com/en-us/help/12407/microsoft-account-change-email-phone-number to rename your personal account (which is an irreversible change). Once the personal account is renamed, the JavaScript for OldConvergedLogin would not be required and this error will not pop-up.
For more information, please refer to: https://support.office.com/en-us/article/which-account-do-you-want-to-use-2b5bbd7a-7df6-4283-beff-8015e28eb7b9
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