@pdonias Thank you for the response.

I confirmed a smaller amount of groups resolved the issue, we simply created an OU which we then searched on for specific groups related to XCP / XOA

I am receiving the following error when attempting to synchronize groups:

ldap.synchronizeGroups
{}
{
  "code": 4,
  "message": " Code: 0x4",
  "name": "Error",
  "stack": "Error:  Code: 0x4
    at Function.parse (/usr/local/lib/node_modules/xo-server-auth-ldap/node_modules/ldapts/StatusCodeParser.ts:61:16)
    at Client._sendSearch (/usr/local/lib/node_modules/xo-server-auth-ldap/node_modules/ldapts/Client.ts:648:30)
    at Client.search (/usr/local/lib/node_modules/xo-server-auth-ldap/node_modules/ldapts/Client.ts:610:5)
    at AuthLdap._synchronizeGroups (/usr/local/lib/node_modules/xo-server-auth-ldap/src/index.js:340:45)
    at Api.#callApiMethod (file:///usr/local/lib/node_modules/xo-server/src/xo-mixins/api.mjs:366:20)"
}

Configuration of the Synchronize groups is:

Filter = (ObjectClass=group)
ID Attribute = dn
Displayname Attribute = cn
group attribute = member
User Attribute = dn

I have tried to mirror the settings as per:
https://xcp-ng.org/forum/topic/3760/ldap-plugin-syncing-groups-from-windows-ad-server-2016-help/3?_=1709316308851

and I am still receiving the same error as above.