1. For iPhone devices, please download the APN profile from the following link:  ➡　In preparation
  2. Check if your 4G function is activated:
    • [Settings]
    • → [Cellular]
    • → [Cellular Data Options]
    • → [Enable 4G]
    • → Choose [Voice & Data] or [Data Only]
  3. Turn OFF “Data roaming” function and Restart your phone.