The mobile phone can answer the phone, but it can't send text messages online. What happened?

If you can't surf the Internet through mobile data, suggestions: Note: If you surf the Internet in different places, please turn on your roaming function first: Set-More Networks-Mobile Networks-Data Roaming (Set-Data Usage-Menu Key-Data Roaming) 1. Make sure that the SIM card of the mobile phone is enabled for Internet access. 2. Pull down the screen top curtain, light up the mobile data, and turn off the WLAN. Note: If the mobile phone is dual-card dual standby, you need to switch SIM card 1/SIM card 2 to surf the Internet. Operation: Settings-Move data-Open the slider in the upper right corner of the screen (green means open)-Use card 1 data/use card 2 data (at present, most telecom CDMA dual-card mobile phones on the market do not support using GSM card to surf the Internet). 3. Reset the Internet parameters (Settings-More Settings-Mobile Network-Access Point Name-Menu Key-Reset to Default Settings), and try to turn off and restart the phone after the reset. 4. Create a new APN: Settings-More Settings-Mobile Network-Mobile Access Point-Access Point Name-Menu Key-Create a new APN (parameters can be consulted with the network operator). (Settings-More Networks-Mobile Networks-Mobile Access Point-Access Point Name-icon in the upper right corner of the screen) 5. If the above operations fail to solve the problem of being unable to access the Internet, please change the SIM card of another mobile phone and try again, or try again at another time or network environment. 6. Back up data (contacts, text messages, pictures, etc. ) and restore factory settings (Settings-Reset/Privacy/Personal-Restore Factory Settings). 7. Try again after upgrading your phone. 8. If the problem still exists, it is recommended that you take the purchase invoice, maintenance card and mobile phone to the local service center for professional engineers to help you test.