Unable to apply for E5 developer program

Hi @Juneyong Park (junepar)

Please note that this is the ko-kr forum. We kindly recommend posting your question in Korean so that more community members can assist you. Alternatively, you may consider posting in the en-us forum if you prefer to use English. We sincerely appreciate your understanding.

Based on similar cases shared by other users, the cause does not always appear to be the phone number itself. Some users reported that switching networks helped them pass the verification check. For example, moving from a mobile hotspot to a home/office broadband connection, while others reported the opposite and were successful when switching from Wi‑Fi to LTE/5G. This suggests that network environment or IP reputation may play a role in the validation process in some scenarios, although there is no official Microsoft documentation confirming the exact criteria used.

Reference: Your phone number did not pass security checks E5 Sandbox - Microsoft Q&A.

Since you've already tried browser-related troubleshooting, it may be worth testing from a different network connection (for example, home broadband, corporate network, or a mobile LTE/5G connection). However, results can vary depending on the environment. If the issue continues across multiple networks, you'll likely need to contact Microsoft Developer Support, as the verification check is performed on the service side.

Please note that this is a paid support ticket, which means it requires an active support plan or a one-time support purchase. However, the benefit of using this channel is that your inquiry will be routed directly to the Microsoft Product Group responsible for the specific service or feature in question. This team includes engineers and developers who work on the product itself, so they are best positioned to provide accurate, in-depth, and authoritative answers especially for complex or edge-case scenarios that go beyond publicly available documentation or community knowledge. 

Thank you for your understanding. 

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