Error: "Oops, something went wrong while loading" [SEE APPROVED ANSWER]

Just cleared issue on my device.
I am using Safari on Mac OS Ventura.
I followed the support team recommendation for Safari in Mac OS Ventura. And only did the steps mentioned below. ( https://support.1password.com/connect-1password-browser-app/#if-youre-using-macos-ventura-or-later ) Scroll down to ‘If you are using Mac OS Ventura or later’.
I went into Mac System Settings> General> Allow in the background. I saw that I had 1 Password 7 and 8 enabled. I disabled 1Password 7 and the trouble vanished and the plug-in appears to now be fully functional. 1 Password 8.10.9 and plugin 2.14.0. (1 Password 7 may have been installed during my earlier troubleshooting steps)

I'll get onto the suggested fixes shortly, but just wanted to float an idea here.
It seems we've got a 'friendly' crowd here, 1Password. Perhaps consider something like an 'insiders' release. That way, us friendlies can do a first round real world test for you before releasing into the wild. I've got a family subscription and 1Password is my elderly mother's lifeline. When things like this happens, it takes a lot of effort to get her processes aligned again, including having to explain why the known process doesn't work anymore.
Just a thought...

Now fixed for me. I removed the extensions from both Chrome and Edge. I also deleted the 1Password for Safari app from my Applications folder. I then restarted my MacBook Pro. Once it restarted, I reinstalled the browser extension for both Chrome and Edge. I also re-downloaded 1Passsord for Safari from the Mac App Store. After that, we’ll three browsers worked fine with 1Password.

I had this issue, Mac Book Pro, latest OS (13.4.1 (c), 1P app (8.10.9) and Safari extension. I uninstalled the app and extension then reinstalled, same issue using the browser extension. It is showing 0 entries when searching, showing 0 vaults etc on a blank tab and then if I go to a site, I get the OP error.

I did as @selfisch mentioned - created a new entry in the main app - just used fake website, made up username and password - now the plugin appears to be working partially. I can click the extension button in the browser bar and it shows logins but trying to autofill the text boxes with selecting 'Autofill' or clicking the 1 password icon inside the text boxes does nothing. I have to copy/paste the entries over.

I have turned off the integrate with 1Password app setting in the browser extension settings.

edit: I have now turned off "Connect with 1Password in the browser" setting in the main 1Password app settings. This is in addition to the extension setting change I mentioned. This seems to have worked to get autofill working again.

Is it no longer possible to reply to a specific comment in a thread on this forum? I'm trying to reply to 1P_Tommy
and his official response from 8:07am this morning. His answer assumes that there is a 1Password icon in the browser. For me, there is not. Neither in the menu bar nor in the Preferences > Extensions. I'm using Safari. I have deleted and reinstalled 1Password for Safari three times so far, in slightly different ways. I have restarted Safari and my computer. Launching Safari normally shows no sign of 1Password inside of Safari. I have also tried launching 1Password for Safari via the Finder before launching Safari, and, alternatively, after launching Safari. In all cases, I can not see any trace of 1Password within Safari. I'm using Safari 16.6 on a mid-2015 MacBook Pro running macOS 12.6.8. This computer model cannot be upgraded to Ventura. System Preferences reports that everything is up to date.

I can add that the primary fix (turning the extension off and then on again) doesn't work consistently on Brave on Linux.

Just throwing in my 2 cents - also doesn't work on Edge. The Add-On comes up blank with no content. The Desktop App works fine, but Extension in Edge is empty.

I will attempt to use the resolution above temporarily. Thank you.

EDIT: Removing the Shared Lock State works on Edge as a temp solution.

Also, it took me ages to find the correct URL to log into the community site to post this question. When logged into https://my.1password.com/home > click my profile picture on top-right > Help & Support > opens https://support.1password.com/category/accounts/ in a new tab > contact support on top-right > redirected to https://support.1password.com/contact/ but not signed in despite being the same browser session. Clicked sign in, which takes me back to https://my.1password.com/signin to sign in again, to repeat this ad-infinitum.

I opened google chrome today (one of several profiles I use on this PC). When I used my keyboard shortcut to open the plugin and log in (Ctrl + Shift + Space), the plugin appeared with the error "Oops, something went wrong". It works when accessing it via other Chrome profiles (same 1password account).
Screen recording of the issue here: https://imgur.com/a/KcHUuhs

1Password Version: 1Password for Windows 8.10.9 (81009046)
Extension Version: 2.14.0
OS Version: Windows 11 Professional
Browser: Chrome 115.0.5790.171 (Official Build) (64-bit)

…nevermind… I spoke too soon.