diff -up openssh-8.6p1/sshd.c.log-usepam-no openssh-8.6p1/sshd.c
--- openssh-8.6p1/sshd-session.c.log-usepam-no	2021-04-19 14:00:45.099735129 +0200
+++ openssh-8.6p1/sshd-session.c	2021-04-19 14:03:21.140920974 +0200
@@ -1749,6 +1749,10 @@ main(int ac, char **av)
 			    "enabled authentication methods");
 	}
 
+	/* 'UsePAM no' is not supported in our builds */
+	if (! options.use_pam)
+		logit("WARNING: 'UsePAM no' is not supported in this build and may cause several problems.");
+
 #ifdef WITH_OPENSSL
 	if (options.moduli_file != NULL)
 		dh_set_moduli_file(options.moduli_file);
diff -up openssh-8.6p1/sshd_config.log-usepam-no openssh-8.6p1/sshd_config
--- openssh-8.6p1/sshd_config.log-usepam-no	2021-04-19 14:00:45.098735121 +0200
+++ openssh-8.6p1/sshd_config	2021-04-19 14:00:45.099735129 +0200
@@ -87,6 +87,8 @@ AuthorizedKeysFile	.ssh/authorized_keys
 # If you just want the PAM account and session checks to run without
 # PAM authentication, then enable this but set PasswordAuthentication
 # and KbdInteractiveAuthentication to 'no'.
+# WARNING: 'UsePAM no' is not supported in this build and may cause several
+# problems.
 #UsePAM no
 
 #AllowAgentForwarding yes