I found and fixed the problem. In short, the domain policy setting was overwriting the Local Security Policy -> "Log on as a batch job"
In the Eventviewer I see the following message, with the same message that is send by the browser.
"Unable to get object: LicenseInfo
Retrieving the COM class factory for component with CLSID {F470B218-7754-4943-92A5-D264627DD361} failed due to the following error: 8000401a The server process could not be started because the configured identity is incorrect. Check the username and password. (Exception from HRESULT: 0x8000401A).
Component: Tridion.ContentManager.CoreService
Errorcode: 3
User: NT AUTHORITY\NETWORK SERVICE
StackTrace Information Details:
at Tridion.Licensing.LicenseInfo..ctor(String productName, LicenseLockType lockType, String licenseFileName)
at Tridion.Licensing.LicenseManager.GetLicenseInfo(String productName, LicenseLockType lockType)
at Tridion.Licensing.LicenseManager.GetLicenseInfo(String productName, LicenseLockType lockType)
at Tridion.ContentManager.LicenseHelper.StartupLicenseCheck(Session session)
at Tridion.ContentManager.Session..ctor(String userName, String impersonationUserName)
at Tridion.ContentManager.CoreService.CoreServiceBase.Impersonate(String userName)
at SyncInvokeImpersonate(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
at Tridion.ContentManager.CoreService.CoreServiceInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)"
Now since this issue is coming up regularly, but not at a exact time, I figured there has to some kind of external process that was messing the server configuration up. Then I read something that the message "Check the username and password" also occurs, when the service can not 'log on as a batch job'.
Right now, when I configure the correct password, I am able to spawn the process, shutdown, spawn again, repeat. As soon as the password is configured, the process is granted "log on as a batch job" rights automatically on the server. You can check this with secpol.msc (rsop.msc doens't work I found).
As soon as the group policy is been updated, these values get overwritten and the service can't start anymore, causing the 'password incorrect' error. You can forcibly test this by running "gpupdate /force". And there it goes: it doesn't work anymore!
I have now added a domain policy, adding the domain MTSUser to "log on as a batch job". This fixes the problem permanently.