Why can't Samsung mobile phones be used when international roaming is turned on?

If Unicom users have passed the function of international roaming and roaming in Hong Kong, Macao and Taiwan, but cannot use this function when roaming in international roaming and roaming in Hong Kong, Macao and Taiwan, there may be the following reasons:

1. Some countries or regions have different network standards and frequency bands, so it is necessary to replace appropriate mobile terminals to use the international roaming function;

2. The mobile phone is set to automatically select the network, and no operator can be found to cooperate with our company. You can manually select a network by changing the setting to "Select Network Manually".

If the above problems cannot be solved, you can call the international roaming, Hong Kong, Macao and Taiwan roaming customer service hotline+8618618610010 for consultation.