Hi Leonardo,
Thank you for your reply.
We have managed to narrow down the error further by commenting out a large section of the .Net code in our application where the UltimatePDF is running.
We are running this code
Actions.ActionPrintToPDF_Advanced(heContext,"https://www.google.co.uk", ENPaperSizeEntity.GetRecordByKey(ObjectKey.Parse("CodeRedacted")).ssSize, ENMarginSizeEntity.GetRecordByKey(ObjectKey.Parse("CodeRedacted")).ssSize, out localVars.resPrintToPDF_Advanced_outParamPDF);
After this is ran we are receiving the following feedback message:

"An error occurred when trying to print to pdf https://www.google.co.uk"
In C:\windows\Temp - IUSR, IIS_IUSRS, IIS AppPool and our own Application Pool which we use for our applications all have full control to that folder. I have also checked in C:\windows\System32\inetsrv and that folder has full control as well for IUSR, IIS_IUSRS, IIS AppPool and our own Application Pool.
In C:\Windows\Temp, .local-chromium is present, before the detach the UltimatePDF was working perfectly fine.
We are unable to check Service Center as we have detached our applications, but would appreciate any guidance you can provide, in case we are missing a location which is missing permissions.
Kind Regards,
Waqar Ahmad