Renewing topic, still didn't find answer yet 🙁 Any idea guys? As I said MySQL is working, so I think this problem is not about password.

Well, running out of ideas really.

I can verify my own windows 2016 on both live and test lab run fine (with local portal and remote portal).

My main question would be: how is your IIS Setup?

as mine is left default, (and installed with the powershell script in the manual).

I do always make sure i disable Windows auth in portal, enterprise and server, and generate machine key.

for Application pools i set the recycle time from 1740 to 0 and timeout from 20 to 0 for all SolidCP App pools.

no other settings such as caching, or anything else i touched.

I have also as you say disabled Windows auth in: portal, ent, server

Also generated machine key in: portal, ent, server as in Installation video

Same for pools as in Installation video.

Version of my IIS 10, when I first occured error I removed IIS 8 from SolidCP panel :/ Before I even started Installation on fresh OS, I installed all requirements in PowerShell.

Just one question I dont understand what do you mean by "as mine is left default"

The left default bit:

You can apply tons of custom settings on the root of the server (which applies to all sites below). with my company i saw alot of people with mysterious IIS issues simply due to custom filter / cache / and other iis settings.

In my case i do not make any custom settings on the IIS Management.

just run powershell command included in my manuals, install solidcp through installer, add the services in the portal.

once that works i start hardening the server, and wrap it up.

(did the same for my Windows 2016 tech preview, and now the official release for some customers without issues).

Well I only installed Webdeploy on root and installed PHP thats all :/ I will continue my try to resolve this problem.