diff --git a/Software/src/devboard/webserver/settings_html.cpp b/Software/src/devboard/webserver/settings_html.cpp
index 5ebcc558..08ca1929 100644
--- a/Software/src/devboard/webserver/settings_html.cpp
+++ b/Software/src/devboard/webserver/settings_html.cpp
@@ -1249,14 +1249,14 @@ const char* getCANInterfaceName(CAN_Interface interface) {
@@ -1266,8 +1266,8 @@ const char* getCANInterfaceName(CAN_Interface interface) {
+ pattern="[A-Za-z0-9!#*-]+"
+ title="Optional: Hostname may only contain letters, numbers and some special characters: !#*-" />
@@ -1312,11 +1312,11 @@ const char* getCANInterfaceName(CAN_Interface interface) {
min="1" max="65535" step="1"
title="Port number (1-65535)" />
+ pattern="[A-Za-z0-9!#*-]+"
+ title="MQTT username can only contain letters, numbers and some special characters: !#*-" />
+ pattern="[A-Za-z0-9!#*-]+"
+ title="MQTT password can only contain letters, numbers and some special characters: !#*-" />