iPhone:
1.setting->mobile internet->mobile data network->input ”multibrand” in APN column (If there is a personal hotspot APN on the same page, please input ”multibrand” too).
2.If you are still unable to use the Internet, check: setting->normal->reset->reset the internet setting
3.After resetting the internet, please go back to step 1 and confirm the APN setting.
Android:
1.setting->mobile internet->mobile data network->input ”multibrand” in APN column (If there is a personal hotspot APN on the same page, please input ”multibrand” too).