Please see this thread for reference. I am having this same problem with a brand new SB6190.
I was on a Netgear CM-400 until Tuesday, when i installed my SB6190 due to ongoing issues (outside my house, for 8 years: a leaky junction box which rusts my connectors that I am still attemtping to resolve, despite the issue being identified twice and it being documented thoroughly in my notes). When I connected on Tuesday, everything went fine. It downloaded the proper firmware (saw the MIMO in the logs and noted the version in the GUI) and activated with Comcast. Then the tech came on Thursday, and everything went to <Edited>.
I am not unable to access my modem's GUI due to the firmware issue, and ALSO now can't reboot my modem. If I do, I have to re-activate it with XFinity's service. I can get into my GUI but when I do, the timestamps in the log are all an hour behind. The system time on my modem is an hour behind me (i'm on CST but my moddem is still on CDT), and occasionally I can't log in at all as the modem tells me there's another local user logged in. This happens EVEN AFTER a reset. This keeps happening even after performng three 30/30/30 resets.
This isn't an issue on my end. I have spent countless hours on the phone with techs in the last week. I spent pretty much all day on the phone yesterday with Xfinity techs (shout out to Tennessee, y'all are INCREDIBLE) and ARRIS techs. This is an issue on XFINITY/ARRIS's end that needs resolution for ALL customers using an SB6190, immediately.
I will be contacting support again on Monday (as I know weekend support is thin), but I needed to make this help post because I cannot spend all of my freetime continuing to troubleshoot *my network* for an issue that is not my fault but has a complicated solution.
I have struggled with intermittent connectivity working from home for 8 years because of that leaking junciton box rusting my connectors in about 2 years time. Trying to get Xfinity to *acknowledge* the issue and then fix it took four years the first time, and I'm now 2 years in on getting it fixed properly (shout out again to Tennessee for getting techs on the outside issue, not sending another install tech to do nothing and charge me $50).
I know the techs work hard, and things are swarmed right now. I was one of them for a long time. I know you all are also doing your best, and bureucratic red tape and poor comunication can muck things up. but **8 years*** of connectivity problems on first my account with my spouse and then my own post-divorce is negligence.
I need to avoid having to deal with level 1 chat techs, who CONSTANTLY tell me I have to contact ARRIS. I have. This isn't their problem. Please help.