Updated xcp-ng-pv-tools on my one XCP 8.2 server. (We have mostly (citrix)7.1 and (xcp)7.6 because of hardware RAID limitations)
Found the ISO located at /opt/xensource/packages/iso. (verison 8.2.0-9)
Moved this to my local workstation, and then to my ISO-repo file server.
Went to my XCP 7.6 server, and then to the Rocky Linux 8.4 VM i just set up.
Removed the EPEL xe-guest-utilities-latest package. (7.21.0-1)
Mounted the XCP ISO from the ISO-repo and installed the guest tools from that. (7.20.0-9)

Agent detected! and the service seems to run without error.

Updated to Master build, a66ae, xo-server 5.92.0, xo-web 5.96.0.
Consoles seem to work fine again.
thanks all!

@florent
I ran the install upgrade script from @ronivay with the fix_console_proxy_xcp_7x branch. Seems to be working.

Can't create Private Network, on XO 5.83

I got to the Pool page, and select Network tab, and then, Select Manage. Add a network, and then hit the Private button. It makes me select a PIF, but anyone I select, and hit go, gives me an error.

I've seen instructions, and they seem pretty easy, so not sure what im doing wrong here.

Doing so in XCP-Center worked fine.

sdnController.createPrivateNetwork
{
  "poolIds": [
    "8e059584-1d7b-b674-1fe4-ef5cd08d2550"
  ],
  "pifIds": [
    "566e0925-72d9-f3c3-6c06-b05ab7035018"
  ],
  "name": "dfg",
  "description": "dfg",
  "encapsulation": "gre",
  "encrypted": false
}
{
  "message": "no connection found for object 8e059584-1d7b-b674-1fe4-ef5cd08d2550",
  "name": "Error",
  "stack": "Error: no connection found for object 8e059584-1d7b-b674-1fe4-ef5cd08d2550
    at default.getXenServerIdByObject (file:///opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server/src/xo-mixins/xen-servers.mjs:197:13)
    at default.getXapi (file:///opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server/src/xo-mixins/xen-servers.mjs:478:29)
    at default.getXapiObject (file:///opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server/src/xo-mixins/xen-servers.mjs:484:17)
    at Xo.getXapiObject (/opt/xo/xo-builds/xen-orchestra-202111011545/node_modules/lodash/_createBind.js:23:15)
    at map (/opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server-sdn-controller/src/index.js:716:46)
    at Array.map (<anonymous>)
    at SDNController._createPrivateNetwork (/opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server-sdn-controller/src/index.js:716:27)
    at Object.call (/opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server-sdn-controller/src/index.js:363:12)
    at Api.callApiMethod (file:///opt/xo/xo-builds/xen-orchestra-202111011545/packages/xo-server/src/xo-mixins/api.mjs:304:33)"
} 

pulled and rebuilt and plugins have returned!

Updated to Master build, a66ae, xo-server 5.92.0, xo-web 5.96.0.
Consoles seem to work fine again.
thanks all!

@florent
I ran the install upgrade script from @ronivay with the fix_console_proxy_xcp_7x branch. Seems to be working.

I don't know if this helps:
most of my VMs are Windows. There are a few Linux, Centos 7+, Rocky, and Ubuntu 18.
the production XO I use, is behind an Apache reverse proxy, using https. The temporary one, is just XO, using http on 8080. Looks like all of these are PVHVM, (so, HVM?) it claims. Both of these XO's are VMs on the same host, and the other hosts are on the same subnet, but some are on a different VLAN. There are also a number that are in a co-location facility, connected via a point to point fiber link, on a different VLAN, but all behind our edge router.
Console working: XCP 8.1, XS 7.1
Console not working: XCP 7.6 - I can't say for sure that these have any updates applied, though.

@olivierlambert
hrm, well, I bumped my temp install of XO back to the master branch, and consoles broke. -Appears- to only broke with XCP 7.6. 7.1, sites worked.

@olivierlambert , I received exact instructions from @ronivay on how to do that. Using commit b9ff3db9b in my new temporary install of XO, everything works fine.
Moving to c99120b seems to break the console on anything other than XCP 8.2.
And I've mentioned before I think: all of our hardware does support XCP 8.2, but almost none of the RAID card monitor software works there. 80% of them are using 3Ware/ LSI 9750's. I can't recall the exact problem, but the executable for the web-admin doesn't run.

after googling some git commands; im not very versed in git at all, so not sure how to get that.
this is the one that last worked for me, and the one im currently using. I save the last 3 in @ronivay script.
v5.16.0-8953-g04913cabb

this is the one that I pulled and it seems to break:
v5.16.0-9058-gf6e1b9571

I see another comment on the issue tracker from @ronivay. I'll try to get to his suggestion a little later.
and just to link these two together for someone in the way future:
https://github.com/ronivay/XenOrchestraInstallerUpdater/issues/116

bberndt created this issue in ronivay/XenOrchestraInstallerUpdater

closed VM console not working in XO. #116

Made another VM with Rocky Linux 8, and a copy of the existing to duplicate my set up. Added some hosts to it, and sure enough same problem. Tried to pull an update to XenOrchestraInstallerUpdater, but its already up to date, and the author says its auto-updates.
So far, not finding a common thread, between them showing up and not showing up. Happens in Firefox, and Chrome, Doesn't appear tob e related to Xen Guest Tools version, getting device drivers from MS or no, or version of XenServer.
As long as im on this old version of XO, it seems to work.

I do see these when i bring up a VM console that doesn't show, and DON'T see them when one does show.

Failed when connecting: Failed to connect to server ( (code: 1005)) util.js:44:54
    Error util.js:44
    _fail rfb.js:578
    f rfb.js:233
    onclose websock.js:305
    open websock.js:307
    _connect rfb.js:384
    _updateConnectionState rfb.js:546
    connect rfb.js:279
    p react-novnc.js:106
    componentDidMount react-novnc.js:111
    React 12
    listen EventListener.js:29
    React 29

Tried changing state of a disconnected RFB object util.js:44:54
    Error util.js:44
    _updateConnectionState rfb.js:473
    disconnect rfb.js:284
    _clean react-novnc.js:66
    p react-novnc.js:72
    (Async: setTimeout handler)
    _onUpdateState react-novnc.js:44
    _updateConnectionState rfb.js:519
    _fail rfb.js:588
    f rfb.js:233
    onclose websock.js:305
    open websock.js:307
    _connect rfb.js:384
    _updateConnectionState rfb.js:546
    connect rfb.js:279
    p react-novnc.js:106
    componentDidMount react-novnc.js:111
    React 12
    listen EventListener.js:29
    React 29
        trapBubbledEvent
        listenTo
        z
        _updateDOMProperties
        mountComponent
        mountComponent
        mountChildren
        _createInitialChildren
        mountComponent
        mountComponent
        mountChildren
        _createInitialChildren
        mountComponent
        mountComponent
        performInitialMount
        mountComponent
        mountComponent
        performInitialMount
        mountComponent
        mountComponent
        performInitialMount
        mountComponent
        mountComponent
        performInitialMount
        mountComponent
        mountComponent
        performInitialMount
        mountComponent
        mountComponent

Is there any reason this might happen if my Xen Server is Citrix 7.1, or XCP 7.6? This is the current suspicion, after a suggestion from the writer of the install script.

Updated to a newer Xen orchestra recently, didn't record what version. But noticed today, that the VM console for a LOT of VMs is broken, and doesn't show up. XCP-ng Center still works fine.
Tried restarting the toolstack on one host, made no difference. Use the XenOrchestraInstallerUpdater to go to update, today, and it didn't fix anything Went back to the earliest version I had, that I can roll back to, and the consoles seem to work again. The working version is: build 04913 5.89/ 5.94.

Any ideas?

Ahh! Alarms on the Dashboard page...