What should I do if Samsung S5 prompts "not registered on the network" that it cannot call?

When I called Samsung S5 G9008V yesterday, the screen suddenly indicated "not registered on the network" and the call was not allowed, at first, I thought it was a network problem, but after carefully reading the network signal is full, I will see the "triangle exclamation mark" icon in the upper left corner. What is the cause of this problem and how to solve it, later I thought it was a problem with network settings. I found that the problem was solved by selecting the "select automatically" option in the "available network" setting area, the following is a demonstration.

Figure 1:

 

1. Click application on the standby page ].

 

2. Click set ].

 

3. Click more networks ].

 

4. Click [mobile network ].

 

5. Click [network operator ].

 

6. Click [select automatically] to search automatically.

 

After completing the preceding operations, the triangle exclamation point icon in the upper left corner disappears and displays "registered on the network ".

 

Tip: If the problem persists after the preceding operations, perform the following operations:
1. Try to replace another Sim card.
2. Restart your phone and try again.

Okay. Generally, we 'd better choose automatic. This will help us automatically try different networks. Sometimes, if we use China Unicom, it won't work if we select a mobile network. It's not 3 GB, switching between 2G networks.