The Quick Answer:

This usually happens if the SIM card is inserted backward, if your data plan is not fully activated yet, or if the router needs to be manually told which cellular network to connect to.

Troubleshoot:

1. Check if the SIM card is properly inserted and detected.

Enter the 192.168.0.1 in a computer browser address bar to log in the router management web.

If the interface displays “No SIM card Inserted” as the following pictures, it manifests that the router cannot detect your SIM card.

Solution:

(1) Reinsert the SIM card, making sure it is inserted correctly and securely.

(2) Reboot the router with the SIM card still inserted into the router.

(3) Please test the SIM card on your smartphone to make sure the SIM card itself is working properly.

(4) Insert another SIM card into the router to test if it's the slot's issue.

(5) Reset the router by pressing and holding the RESET hole for at least 5 seconds until all LEDs blink.

2. Enter the SIM Card PIN Code to unlock it

Restarting the device or plugging in or out of the SIM card will require the PIN code to be unlocked again, as shown in the pictures.

Solution:

(1) Click Please unlock the SIM card,

(2) Enter your PIN code and click the Save button.

Note: If you are not sure about your PIN code, please do not keep trying, or your SIM card will be locked, and a PUK code will be required. Please contact your SIM card carrier to get your PIN or PUK code.

3. Configure the network password (APN)<click here>

If the SIM works perfectly in a phone but not in the router, your router just needs your carrier's network password (called an APN). Connect to your router's Wi-Fi, open a web browser, and type 192.168.0.1. If the interface displays “Connecting failed” as the following pictures.

Solution
(1) Please go to Internet Setting > Dial-up Settings to check the current profile settings. Check the drop-down list of the Profile Name to see if there is any other available profile; if so, try another profile to see if it works.

(2) Make sure the Network Mode is on “4G Preferred” and Band is on “Auto”.

(3) Create a new profile and enter the APN, username, password, and authentication type manually<click here>; if you're unsure about the correct settings, contact your SIM card provider for confirmation.

(4) Click the Save button after each step, then reboot your router to apply the settings.

If issues persist after following these steps, contact Tenda Technical Support via tendafwa@tenda.cn with the following details:

(1) Model number, hardware, and firmware version

(2) Your country, SIM card carrier

(3) Please screenshot the Internet Status page and the APN Profile Settings page. Then go to System Settings > System Log to export the log file. Please package all the above files and send them to us.

(4) Troubleshooting you’ve taken and the results for each step