Hello,
Welcome to the Microsoft Community.
Have you tried connecting to other displays wirelessly?
The Surface Pro 11 supports Miracast but no longer supports the old Intel WiDi. The LeTV TV may have compatibility issues with Miracast.
WiDi (Wireless Display) is a proprietary screen-casting protocol launched by Intel around 2010, relying on a combination of specific Intel processors, integrated graphics, and wireless network cards. System Requirements for Intel® Wireless Display (Intel® WiDi)
Early TVs (especially models before 2015) may only support WiDi or proprietary protocols. Even if they claim to support Miracast, some TV firmware has compatibility issues.
Therefore, it is recommended to test connecting to other TVs that support Miracast to confirm whether the connection is possible.
Best regards,
Huy-K | Microsoft Community Support Specialist