diff --git a/tailscaleAuth.go b/tailscaleAuth.go
index 794554a..ff7c6bb 100644
--- a/tailscaleAuth.go
+++ b/tailscaleAuth.go
@@ -7,6 +7,7 @@ import (
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp/caddyauth"
 	"net/http"
 	"strconv"
+	"strings"
 	"tailscale.com/client/tailscale"
 	"time"
 )
@@ -35,7 +36,7 @@ func (ta *TailscaleAuth) Provision(caddy.Context) error {
 
 	ta.allowedUsersMap = make(map[string]struct{})
 	for _, u := range ta.AllowedUsers {
-		ta.allowedUsersMap[u] = struct{}{}
+		ta.allowedUsersMap[strings.ToLower(u)] = struct{}{}
 	}
 
 	return nil
@@ -52,7 +53,7 @@ func (ta *TailscaleAuth) Authenticate(_ http.ResponseWriter, req *http.Request)
 		return caddyauth.User{}, false, err
 	}
 
-	if _, found := ta.allowedUsersMap[whois.UserProfile.LoginName]; len(ta.allowedUsersMap) != 0 && !found {
+	if _, found := ta.allowedUsersMap[strings.ToLower(whois.UserProfile.LoginName)]; len(ta.allowedUsersMap) != 0 && !found {
 		return caddyauth.User{}, false, nil
 	}