@Saba1990 

The returned error code is wrong username and password. That's the reason why it does not connect. Note that this has passed to the ISP server, unlike what you described, that it has not reached the ISP server and returned an error code. It cannot return the error code before it detects an error code from the ISP. 

You might wanna examine the landline or contact your ISP for this information. 

  @Clive_A, thank you for your quick response. I can connect to the ISP from my Archer MR400 router with the same username and password. MR400 router user PAP for the authentication. Is there any way to force ER605 to use PAP for the authentication?

Also, why the auth is null in ER605.

 2025-07-21 09:07:55 ppp[13579]: <5> 02313101 [OMADA]WAN1: LCP negotiation succeeded. (MTU=1480, AUTH=<null>) 

Thank you,

Saba

  @Saba1990 

Saba1990 wrote

  @Clive_A, thank you for your quick response. I can connect to the ISP from my Archer MR400 router with the same username and password. MR400 router user PAP for the authentication. Is there any way to force ER605 to use PAP for the authentication?

 

Also, why the auth is null in ER605.

 2025-07-21 09:07:55 ppp[13579]: <5> 02313101 [OMADA]WAN1: LCP negotiation succeeded. (MTU=1480, AUTH=<null>) 

 

Thank you,

Saba

No.

Is there a reason that you manually set the MTU? 

MR400 is a mobile router. How did you connect the MR400 before? Using the landline? 

There is no background for this scenario. I don't have any insights, but judging from the returned error code, it is what it is. The ISP PPPoE server rejects the input information from the router. 

  @Clive_A Hi,

My ISP runs a fiber optics cable and have given GPON converter. I have connected the MR400's WAN RJ45 port to the GOPN converter's LAN RJ45 port and used the PPPoE connection to connect to the internet. 

Below is the setting screenshot that is used in the MR400.

In the original post, I have attached the screenshot of the ER605. MTU is set as 1480 in the MR400, so I have tried with the same MTU in ER605 to check if that works.

Please let me know for more information.

Thank you,

Saba

  @Saba1990 

Saba1990 wrote

  @Clive_A Hi,

 

My ISP runs a fiber optics cable and have given GPON converter. I have connected the MR400's WAN RJ45 port to the GOPN converter's LAN RJ45 port and used the PPPoE connection to connect to the internet. 

Below is the setting screenshot that is used in the MR400.
 

 

In the original post, I have attached the screenshot of the ER605. MTU is set as 1480 in the MR400, so I have tried with the same MTU in ER605 to check if that works.

 

Please let me know for more information.

 

Thank you,

Saba

Try the auto mode, set the mode as PPPOE and simply input the username and password. Other specs as default, what's the returned result?

  @Clive_A As you mentioned, I have reset to default settings and added only username and password. But getting the same error.

2025-05-01 10:56:12    PPPoE Client    NOTICE    WAN1: PPPoE began connecting automatically.
2025-05-01 10:56:13    PPPoE Client    NOTICE    WAN1: PPPoE Discovery phase negotiation succeeded. (AC-MAC=78-9a-18-be-56-bf, Session-ID=0xde6a)
2025-05-01 10:56:13    PPP    NOTICE    WAN1: LCP negotiation succeeded. (MTU=1492, AUTH=<null>)
2025-05-01 10:56:14    PPP    WARNING    [osg:DC-62-79-4C-FF-08]: PPPOE ka*** failed to connect to the server because authentication failed with the wrong username or password.
2025-05-01 10:56:14    PPPoE Client    NOTICE    WAN1: PPPoE session is over
2025-05-01 10:58:16    PPPoE Client    NOTICE    WAN1: PPPoE connection was disconnected by peer. (AC-MAC=78-9a-18-be-56-bf, Session-ID=0xde7f)

Below is the settings screenshot.

Thank you,

Saba

  @Saba1990 

Saba1990 wrote

  @Clive_A As you mentioned, I have reset to default settings and added only username and password. But getting the same error.

 

 

2025-05-01 10:56:12    PPPoE Client    NOTICE    WAN1: PPPoE began connecting automatically.
2025-05-01 10:56:13    PPPoE Client    NOTICE    WAN1: PPPoE Discovery phase negotiation succeeded. (AC-MAC=78-9a-18-be-56-bf, Session-ID=0xde6a)
2025-05-01 10:56:13    PPP    NOTICE    WAN1: LCP negotiation succeeded. (MTU=1492, AUTH=<null>)
2025-05-01 10:56:14    PPP    WARNING    [osg:DC-62-79-4C-FF-08]: PPPOE ka*** failed to connect to the server because authentication failed with the wrong username or password.
2025-05-01 10:56:14    PPPoE Client    NOTICE    WAN1: PPPoE session is over
2025-05-01 10:58:16    PPPoE Client    NOTICE    WAN1: PPPoE connection was disconnected by peer. (AC-MAC=78-9a-18-be-56-bf, Session-ID=0xde7f)

 

Below is the settings screenshot.

 

 

 

Thank you,

Saba

Who's your ISP? Did you contact them regarding that? I highly recommend you contact your ISP support regarding this first if they require a setting on the router to make it work. 

If you want to dive into this, I will need the result of Wireshark because the current log does not tell details about it. I assume the PPPOE returns the error code, and the error code matches the PPP protocol, which translates into wrong username and password. 

  @Clive_A , Thank you for your response. My ISP is SBASS - a regional internet provider. They allow us to use our own routers to connect to them. In-fact the Archer MR400 is my own router to connect to the internet. I will have a word with the ISP.

Thank you,

Saba

Hi @Clive_A ,

After tracing the packets with Wireshark, ER605 router is sending the below packets to the ISP for the authentication.

0000   78 9a 18 be 56 bf dc 62 79 4c ff 09 88 64 11 00
0010   df 53 00 23 c0 23 01 53 00 21 15 73 62 61 73 73
0020   2d 6b 61 6e 61 67 61 73 61 62 61 70 61 74 68 79
0030   06 31 32 33 34 35 36 00 f1 49 6f 94
 

I can see a null byte after the password.  Will that be a problem for the authentication failure?

Because of that, the ISP returns 'Login Incorrect' response as below.

0000   dc 62 79 4c ff 09 78 9a 18 be 56 bf 88 64 11 00
0010   df 53 00 16 c0 23 03 00 00 14 0f 4c 6f 67 69 6e
0020   20 69 6e 63 6f 72 72 65 63 74 00 00 00 00 00 00
0030   00 00 00 00 00 00 00 00 00 00 00 00
 

Thank you,

Saba