For the moment Sitecore don't support Windows 11 for installing XM or XP - but since Microsoft have a fairly agressive policy of rolling it out to machines currently running Windows 10 and installing it by default on new hardware, there are a fair few developers out there finding themselves having to work out how to get it to work...
One of my colleages tried to run a Sitecore Install Assistant (SIA) install of v10.2 on his laptop recently, and found that it failed. During the "start up all the services" phase, the Marketing Automation service would not come up. And in the logs for that service, this error (plus a bunch more stack trace) was repeated quite a few times:
Starting Marketing Automation Engine... 2022-06-08 15:51:29 ERR Error initializing XConnect client. System.AggregateException: One or more errors occurred. ---> Sitecore.XConnect.XdbCollectionUnavailableException: An error occurred while sending the request. ---> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.ComponentModel.Win32Exception: The credentials supplied to the package were not recognized at System.Net.Security.SslState.CheckThrow(Boolean authSuccessCheck, Boolean shutdownCheck) at System.Net.Security.SslState.get_SecureStream() at System.Net.TlsStream.EndRead(IAsyncResult asyncResult) at System.Net.Connection.ReadCallback(IAsyncResult asyncResult) --- End of inner exception stack trace ---
(Line-breaks added to make it easier to read)
And obviously the install can't complete at this point, so SIA fails...
I was answering questions about this issue remotely, and didn't immediately think to get on a screen share to investigate this. (my bad) So initially I didn't realise that Windows 11 was a factor here. Googling that error didn't give much in the way of useful hits at the time - mostly Stack Overflow answers which did not refer to Sitecore. But they did seem to refer to SSL Certificates - which was a clue.
But once my colleague realised that Windows 11 might be a factor, the issue was fairly easy to resolve. A useful post from Maarten Willebrands has a write-up of specific issues he'd seen with Sitecore and Windows 11 which hits on the correct answer: The cause of the problem appears to be the default TLS settings in Win 11: TLS 1.3 is on by default in new IIS Sites, but xConnect does not work correctly with this enabled right now. Hence the errors we were seeing.
As Maarten points out in his post, disabling the use of TLS 1.3 in the IIS Site for xConnect will resolve the problem, and allow the Marketing Automation service to start:
So cheers to Maarten for the answer, and hopefully this post will add the alternative error message to Google for future people hitting this issue... Though I am hoping to see a fix from Sitecore with their next release, to either disable this setting automatically in the setup, or to make xConnect compatible.