Please consider asking on an appropriate site, like https://superuser.com/
Post a link here, if you do.

I am sorry for the lack of specifics, you are correct, the problem appears to be in the OpenSSH SFTP server. Profiles belonging to the Administrator group are authenticated, all others fail. By generic user profile, I mean one that is not a member of the Administrator group. I realize that this is not a WinSCP issue, I was hoping others might have already run across this problem and have a solution. The issue seems to be with the SSHD_Config file that is shipped with this feature on Windows Server 2019. I followed the instructions on the WinSCP website to set up an SFTP server, which had me install the OpenSSH feature, but the instructions do not address any possible changes to the default SSHD_config file. Adjusting the AllowUsers and AllowGroups entries in this file do not seem to have the effect I would expect. Has anyone successfully implemented an OpenSSH SFTP server on Windows Server 2019 that will authenticate non-Administrator profiles? The specific error in the SSHD.log shows
"Windows authentication failed for user: FTPUSER.local domain: (null) error: 1329"
The user logging in is gal.ftpuser, gal is our local domain. The testing is being done within the domain.

Sorry, this is too vague and not really WinSCP question.
Anyway, the connection cannot be rejected based on an account. An authentication can be – Is that what you mean? What exact error are you getting? What is "generic FTP profile"? FTP has nothing to do with OpenSSH.

We had to rebuild our Server 2012 R2 network after an unfortunate Update failure, so we upgraded to Windows Server 2019. We had been using WinSCP and OpenSSH on the old server, so we were pleased to find that Microsoft had ported the OpenSSH code into their Server software. I installed the feature per the instructions on the WinSCP website and everything worked great. Unfortunately, I was testing with an Administrator class profile, once I tried our generic FTP profile, the connection is rejected. Has anyone else seen this problem? We are using WinSCP version 5.17.7 (Build 10640)