After the router is restarted, the WAN port cannot be dialed and the connection is always displayed

rebooting the router, the WAN port keeps showing 'Connected' or 'Disconnected', causing broadband dial-up failure?
computer can connect directly to the optical modem for internet access, but connecting to a router doesn't?

the logic for troubleshooting PPPoE dial-up issues is very clear—just follow the order.

Diagnosis: What are the common causes of not being able to dial through the WAN port?

first check the error message in the router's backend. There are three common types:

Common Causes (sorted by frequency):

• PPPoE Incorrect account and password input — most common, as carrier-issued orders are easily misremembered
• the optical modem switches to routing mode, the router cannot be turned — the optical modem has been dialed, but the WAN port has no signal
• network cable connected to the wrong port — the WAN port must be connected to the optical modem (LAN1 (some optical modems have multiple LANs)
• carrier binds a MAC address you need to reauthenticate after changing routers
• the optical modem or broadband itself is faulty — troubleshoot this first, then fix the router

Solution

Option 1: Confirm account and password (first reason for the first number)

most cases where you can't dial a number, it's because you remembered the wrong account or password.

How do you find the correct PPPoE account and password?

1. look for installation work orders from the operator

   • the piece of paper left by the technician during broadband installation is usually affixed to the optical modem or in the delivery list
   • format is usually: username (phone number @adsl) / password (8-digit number)

2. Check the Light Modem backend

   • enter the optical modem address (usually 192.168.1.1) in the browser
   After logging in,
   • find "Network→ "Broadband Settings," → "Internet"
   • account is usually visible, and the password is usually displayed as ******** (mask)
   • some optical modems have a "Show Password" button, which is visible when clicked

3. call the carrier's customer service

   • Move: 10086 | Unicom: 10010 | Telecommunications: 10000
   • provide the owner's name and the last 6 digits of the ID card; customer service can reset the password
   • password will send a text message; it is recommended to change it immediately after resetting

How do you correctly enter your account and password on the router?

1. Log in to the router's backend
2. find "WAN Port Settings" or "Internet Settings"
3. Connection Type Selection: PPPoE
4. Account: Enter the full username (including @ADSL or @whatever suffix
5. password: Enter your password, paying attention to case sensitivity (carrier passwords are usually all digits)
6. Click "Connect" or "Save"

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Common error : Missing @ADSL suffix at the end of the account. The commonly used mobile format is mobile number @adsl, China Unicom uses mobile number @unicom, and China Telecom uses mobile number @adsl or direct phone number.

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pitfalls to avoid:

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• Do not add spaces in the account input box
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• Do not copy or paste accounts with hidden characters (manually delete the preceding and following spaces after pasting)
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• When the password is all numeric, do not add quotation marks; the router will treat the quotes as part of the password

Option 2: Check the modem (most easily overlooked)

optical modem has two working modes:

how do you determine which mode the optical modem is?

1. Log in to the optical modem backend (192.168.1.1 or 192.168.100.1)
2. find 'Network' → 'Broadband Settings'
3. check "Connection Mode" or "Operating Mode":
   • shows Bridge → normal, router handles dialing
   • shows Route / PPPoE / Router → The optical modem has dialed, and the router's WAN port receives the internal IP (usually 192.168.1.x)

What should I do if

optical modem is in routing mode?

Method A: Switch to bridging mode (recommended, most correct)

1. Log in to the optical modem backend
2. find "Network" → "Broadband Settings"
3. delete the original PPPoE connection
4. create a new connection, change the mode to Bridge (or IPoE)
5. save, restart the optical mode
6. connect the router's WAN port to the optical modem (LAN 1), and the router starts dialing up

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note: Some carriers' optical modems have disabled the bridging feature, requiring a maintenance technician to fix it. If you ask customer service to make changes, remember to specify 'Change bridging.'

Method B: Keep the optical modem unchanged, switch the router to AP mode

1. find 'Operating Mode' in the router's backend
2. switch to "AP mode" or "bridge mode"
3. shut down the router's DHCP server
4. optical modem is responsible for dialing and assigning IPs, while the router only handles transmission WiFi

Option 3: Check the network cable and optical modem LAN port

Troubleshooting physical layer issues.

Step 1: Make sure the network cable is plugged in correctly

optical modem usually has multiple LAN ports, but broadband dial-up can only be done using LAN1:

• LAN1 → IPTV + broadband (this is the output port for routing mode)
• LAN2 / LAN3 → may only have internet, no broadband VLAN
• cable type → confirm it is Cat5e or above (required for 100Mbps or more broadband

Step 2: Test the network cable

1. unplug the network cable connecting the router's WAN port
2. plugged directly into the computer's network port
3. set up broadband dial-up on your computer (Windows Control Panel → Network and Internet → broadband connection)
4. enter your account and password to see if you can dial
5. if the computer can dial → network cable and optical modem, the problem lies with the router
6. if the computer cannot turn → optical modem or broadband is problematic

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pitfalls to avoid:

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• Do not reverse-plug the WAN port and LAN port (a common mistake for beginners
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• Do not use poor-quality cables (cables under 30 yuan can easily cause problems
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• Some optical modems have LAN1 dedicated to IPTVs and differ in functionality from LAN2/3

Solution 4: Clone MAC address (carrier binds MAC)

some carriers (especially China Mobile and certain regional Telecom/Unicom) bind the MAC address of the device for the first dial-up, and after switching routers, you need to unbind it.

How do you clone a MAC?

1. on the computer, dial once successfully using the old router (have the carrier register the MAC)
2. Or: Find the "MAC Address Clone" option in the new router
3. enter the old router's WAN port MAC (or computer network port MAC
4. Save and try dialing again

How do you check the router's WAN port and MAC?

• Method A: The label on the back of the router says MAC
• Method B: Router backend → system status → WAN port information → MAC address
• method: C: command line ipconfig /all to look up physical address

Option 5: Contact the Operator to Confirm the Fault

if everything is checked and still doesn't work, it's most likely a problem with the carrier.

check first:

Is the
• modem and PON light always lit? (LOS red light → light signal is off)
• Is there a large-scale network outage in entire buildings or residential communities? (Asking the neighbors)
• just owed the bill? (The easiest to overlook)

What do you say when

report obstacles:

"Router WAN port PPPoE dialing failed, error code 691 (or other), the computer's direct optical modem can access the internet / cannot be accessed, optical modem model xxx, router model xxx. 」

Final reminder

• accounts with suffixes (@ADSL/@xxx) is the most common missed field
• optical modem routing mode is the most easily overlooked reason
Before
• changing routers, it's best to save screenshots of your original account and password
• **Outstanding payments are the most hidden "fault"**; wait 5 minutes after recharging before trying again

Cannot dial = Account/password, optical modem, physical connection—one of the three must be involved. Check in order, don't skip steps.

What broadband do

use? What kind of router? Share your thoughts in the comments, and we'll help you analyze the specific issues.