There are mainly two cases for 4G failed connction when test network connection:
1. If there is no IMEI code, it probably is the issue of 4G module. Hardware not recognized by VBox. Only to replace.
2. If there is IMEI code show up, but failed to obtain IP address of 4G.
There are some measures able to take under this situation happen.
- Please try to update the firmware to the latest version 22111701. If updated failed, please use the old software V-NET Access update first, about this part, please refer to the FAQ What should I do when the V-Box update firmware always failed
- Please try to confirm whether the SIM card is the IoT SIM, is there any domain or port limitation?
- Please try to confirm is there any unpaid bill for SIM card
- Please try to insert the 4G antenna for V-Box
- Check whether there is interference for 4G signal. For example, SIM card insert