diff --git a/setup/so-whiptail b/setup/so-whiptail
index ede138d26..5e2a2de0e 100755
--- a/setup/so-whiptail
+++ b/setup/so-whiptail
@@ -195,10 +195,12 @@ whiptail_create_web_user() {
 	[ -n "$TESTING" ] && return
 
 	WEBUSER=$(whiptail --title "$whiptail_title" --inputbox \
-	"Please enter an email address to create an administrator account for the Security Onion Console (SOC) web interface.\n\nThis will also be used for Elasticsearch and Kibana." 12 60 "$1" 3>&1 1>&2 2>&3)
+	"Please enter an email address to create an administrator account for the Security Onion Console (SOC) web interface.\n\nThis will also be used for Elasticsearch and Kibana.\n\nMust only include letters, numbers, or + - _ % . @ characters. All capitalized letters will be converted to lowercase." 12 60 "$1" 3>&1 1>&2 2>&3)
 
 	local exitstatus=$?
 	whiptail_check_exitstatus $exitstatus
+
+	WEBUSER=${WEBUSER,,}
 }
 
 whiptail_create_web_user_password1() {