Motorola modem certificate error

[RocketJSquirrel]

I have always been able to log in via web to my Motorola MB8600 cable modem... until today.

Now, all browsers are showing certificate errors, and not the same errors.

Firefox says

An error occurred during a connection to 192.168.100.1. You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert.

Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL​

Edge says:

Your PC doesn’t trust this website’s security certificate.

Error Code: DLG_FLAGS_INVALID_CA​

The certificate does not expire until 2039.

I sent an error report to Motorola, but have not heard back. (Who knows who's staffed at all during this health emergency?)

I can bypass the error and get to the modem's web server. I rebooted the modem but that didn't fix the problem. Anybody know what's going wrong and how to fix it?

 

[CaptainSTX]

I have always been able to log in via web to my Motorola MB8600 cable modem... until today.

Now, all browsers are showing certificate errors, and not the same errors.

Firefox says

An error occurred during a connection to 192.168.100.1. You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert.

Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL​

Edge says:

Your PC doesn’t trust this website’s security certificate.

Error Code: DLG_FLAGS_INVALID_CA​

The certificate does not expire until 2039.

I sent an error report to Motorola, but have not heard back. (Who knows who's staffed at all during this health emergency?)

I can bypass the error and get to the modem's web server. I rebooted the modem but that didn't fix the problem. Anybody know what's going wrong and how to fix it?

I firmware update for the modem seems to have caused this issue. With Edge you can proceed to sign in after acknowledging the issue then proceeding to log in. With Firefox you have to delete the certificate on file in the browser and then you can again against Firefox's recommendation log on.

A PITA but since I don't log into my modem more often than weekly I deal with it. When I called Comcast they were clueless or at least the CSRs were.

 

[RocketJSquirrel]

I have been exchanging email with Motorola support. Their suggestion was a hard reset, which is done by disconnecting the coaxial cable (with power still on) and paper-clip pressing the reset button for 25 seconds, then finally reconnecting the coax.

The reset succeeded (it turns out there are lights on the back of the modem which flash on reset), but it did not solve the certificate problem.

Motorola's next suggestion was to return the modem to be exchanged for a new one. I don't think I'll bother.

 

[RocketJSquirrel]

With Firefox you have to delete the certificate on file in the browser and then you can again against Firefox's recommendation log on.

A PITA but since I don't log into my modem more often than weekly I deal with it.

I found the easy solution for Firefox. Delete the existing certificate in the Servers tab of the Certificate Manager. Then create an exception for http://192.168.100.1/ (or whatever your modem's address is) and FF will go to the modem login page without further complaint.