GUI unaccessible after upgrade from 9.10 to 11.3

[galantis]

Today I decided to upgrade my FreeNAS machine from 9.10 to 11.3 via the update functionality of the GUI.
When trying to access the GUI via a browser I got this:

I read other threads suggesting the browser to be the cause, so tried it on several (newly installed) browsers, still all the same message.

I can ping the machine. I can SSH into it as well, but not sure what credentials to enter here. I tried the ones I logged into the webpage GUI normally but those don't work. Also another user of which I'm sure I remember the username/password correctly won't login via SSH.

What are good steps for troubleshooting now?
Do I need to hook-up a screen/keyboard locally to configure something?

And if after I find no fix, I make a fresh USB stick with the OS (preferably 9.10 then) installed on it, I assume it will be able to find and import my existing pool during setup?

Have no access to specific specs right now, but this should come close:
MB: Supermicro x10sil
CPU: Xeon X3430
RAM: 16GB
HDD: 4x2GB WD Red in zraid2
FreeNAS OS from a separate 16GB USB stick

 

[galantis]

I connected a local monitor and a continuous stream of errors was shown which only stopped when I closed the web interface on the remote pc that tried to access the system:

So one saying that connect() failed while connecting to upstream, and the other one related to resolving pool 0.freebsd.pool.ntp.org.

I read somewhere else that restarting the ngnix and django services might help.
For that I need to open somewhere a CLI, which I assume is done from the "Console Setup" menu one is normally presented with when connecting a monitor directly to a FreeNAS machine.
How do I access this menu from here?

 

[galantis]

Just found another topic of which the symptoms seem to match to mine:

Cant connect to web gui after updating

hi i recently got a HPE proliant dl185 g5 storage server ( base specs) and was using FreeNAS for a bit, i then tried to update it from version 9 to 11 and i cant seem to connect to the web gui anymore, i get the first image on my pc when trying to connect and the second is whats displayed on my...

www.ixsystems.com

I read that it is not recommended to skip versions, stupid of me.

If it's true what post #2 in that topic is saying about the old version still being bootable from the grub boot menu, then I would be very happy. Will try this as soon as I can.

If someone has other suggestions, feel free.

 

[SweetAndLow]

Fresh install and upload config could be an easy solution.

 

[galantis]

Fresh install and upload config could be an easy solution.

Yes, but I do not have a backup of the config file.
Can I still retrieve the config from the current USB stick? If so, how do I do this? Create and boot a fresh install on a different USB stick and then attempt to access the old stick?

 

[SweetAndLow]

It should be stored on your main pool if that's where you kept your system dataset. I would get a new USB, fresh install, then browse your system dateset and grab the config. I'm not sure what's required to do that but I think it's possible. Save your old USB just Incase.

 

[galantis]

It should be stored on your main pool if that's where you kept your system dataset. I would get a new USB, fresh install, then browse your system dateset and grab the config. I'm not sure what's required to do that but I think it's possible. Save your old USB just in case.

I managed to boot into the 9.10 install by picking "initial-install" from the boot environment menu. But that loads the default config so still have to upload the one I found in the main pool, as you mentioned. It was located at /var/db/system/configs-***/.
But before messing around with that, I will first make a backup of all personal data. Luckily I was able to recover the existing zpool with ease.