Syslog streaming to RHEL 9 Syslog forwarder receiving a TLS handshake error

We have recently implemented Syslog streaming on our Appian platform.  The log file is reporting a TLS handshake failure. We've been able to successfully use Curl (sample command below) to connect to the syslog server.   We've done an end-to-end packet capture while doing this curl and can't see any evidence of a TLS handshake error.  The certificate we use is a wildcard certificate (i.e. *.oir.qld.gov.au), but Appian support have confirmed this is acceptable.  Examining the packet capture, we can see both a client and server hello, and both are successful.  Because of this, I suspect the error lies within the rsyslog setup on my syslog server. 

Sample Curl Command that reports a successful connection  

curl -ilv OIRPSENTINEL01.oir.qld.gov.au:6514

Setup of rsyslog.conf on our Syslog server

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# rsyslog configuration file

# For more information see /usr/share/doc/rsyslog-*/rsyslog_conf.html
# or latest version online at www.rsyslog.com/.../rsyslog_conf.html
# If you experience problems, see www.rsyslog.com/.../troubleshoot.html

#### GLOBAL DIRECTIVES ####

# Where to place auxiliary files
global(workDirectory="/var/lib/rsyslog")

# Use default timestamp format
module(load="builtin:omfile" Template="RSYSLOG_TraditionalFileFormat")

# Include all config files in /etc/rsyslog.d/
include(file="/etc/rsyslog.d/*.conf" mode="optional")

$DebugFile /etc/syslog/debug.log
$DebugLevel 2
#### MODULES ####
module(load="imuxsock" # provides support for local system logging (e.g. via logger command)
SysSock.Use="off") # Turn off message reception via local log socket;
# local messages are retrieved through imjournal now.
module(load="imjournal" # provides access to the systemd journal
StateFile="imjournal.state") # File to store the position in the journal
#module(load="imklog") # reads kernel messages (the same are read from journald)
#module(load="immark") # provides --MARK-- message capability

# Provides UDP syslog reception
# for parameters see www.rsyslog.com/.../imudp.html
#module(load="imudp") # needs to be done just once
#input(type="imudp" port="514")

# Provides TCP syslog reception
# for parameters see www.rsyslog.com/.../imtcp.html
# make gtls driver the default
$DefaultNetstreamDriver ossl

# certificate files
$DefaultNetstreamDriverCAFile /home/millarbr/syslog/wildcard_ca.pem
$DefaultNetstreamDriverCertFile /home/millarbr/syslog/wildcard_cl.pem
$DefaultNetstreamDriverKeyFile /home/millarbr/syslog/wildcard_key.pem

$ModLoad imtcp # load TCP listener

$InputTCPServerStreamDriverMode 1
# run driver in TLS-only mode
$InputTCPServerStreamDriverAuthMode anon
# client is NOT authenticated
$InputTCPServerRun 6514
# start up listener at port 6514

#module(load="imptcp") # needs to be done just once
#input(type="imptcp" port="514")

#### RULES ####

# Log all kernel messages to the console.
# Logging much else clutters up the screen.
#kern.* /dev/console

# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none /var/log/messages

# The authpriv file has restricted access.
authpriv.* /var/log/secure

# Log all the mail messages in one place.
mail.* -/var/log/maillog

# Log cron stuff
cron.* /var/log/cron

# Everybody gets emergency messages
*.emerg :omusrmsg:*

# Save news errors of level crit and higher in a special file.
uucp,news.crit /var/log/spooler

# Save boot messages also to boot.log
local7.* /var/log/boot.log

-----------------------------------------------------------------

I understand that rsyslog is typically setup for mutual TLS authentication, and Appian only supports server authentication.  I am of the understanding this is achieved via the "$InputTCPServerStreamDriverAuthMode anon" command.  Are there additional commands required?  Does anyone have any other suggestions?