diff --git a/bundles/org.openhab.core.io.http.auth/pages/authorize.html b/bundles/org.openhab.core.io.http.auth/pages/authorize.html
index e4b26dc1386..a2c67d183f8 100644
--- a/bundles/org.openhab.core.io.http.auth/pages/authorize.html
+++ b/bundles/org.openhab.core.io.http.auth/pages/authorize.html
@@ -114,7 +114,7 @@
 			<input class="field" type="{repeatPasswordFieldType}" placeholder="{repeatPasswordPlaceholder}" name="password_repeat" />
 		</div>
 		<div>
-			<input class="field" type="{tokenNameFieldType}" placeholder="{tokenNamePlaceholder}" name="token_name" />
+			<input class="field" type="{tokenNameFieldType}" placeholder="{tokenNamePlaceholder}" name="token_name" required pattern="[a-zA-Z0-9]+" />
 		</div>
 		<div>
 			<input class="field" type="{tokenScopeFieldType}" placeholder="{tokenScopePlaceholder}" name="token_scope" />
diff --git a/bundles/org.openhab.core.io.http.auth/src/main/resources/messages.properties b/bundles/org.openhab.core.io.http.auth/src/main/resources/messages.properties
index ac450af0914..7223a9629be 100644
--- a/bundles/org.openhab.core.io.http.auth/src/main/resources/messages.properties
+++ b/bundles/org.openhab.core.io.http.auth/src/main/resources/messages.properties
@@ -16,7 +16,7 @@ auth.placeholder.username = User Name
 auth.placeholder.password = Password
 auth.placeholder.newpassword = New Password
 auth.placeholder.repeatpassword = Confirm New Password
-auth.placeholder.tokenname = Token Name
+auth.placeholder.tokenname = Token Name (alphanumeric)
 auth.placeholder.tokenscope = Token Scope (optional)
 
 auth.button.signin = Sign In