diff --git a/php/src/Data/ConfigurationManager.php b/php/src/Data/ConfigurationManager.php
index 40ecbdde..60fa28b3 100644
--- a/php/src/Data/ConfigurationManager.php
+++ b/php/src/Data/ConfigurationManager.php
@@ -497,12 +497,15 @@ class ConfigurationManager
         return $config['timezone'];
     }
 
+    /**
+     * @throws InvalidSettingConfigurationException
+     */
     public function SetTimezone(string $timezone) : void {
         if ($timezone === "") {
             throw new InvalidSettingConfigurationException("The timezone must not be empty!");
         }
 
-        if (!preg_match("#[a-zA-Z0-9_-/+]+$#", $timezone)) {
+        if (!preg_match("#^[a-zA-Z0-9_\-\/\+]+$#", $timezone)) {
             throw new InvalidSettingConfigurationException("The entered timezone does not seem to be a valid timezone!");
         }
 
diff --git a/php/templates/containers.twig b/php/templates/containers.twig
index 74ade259..e09f105a 100644
--- a/php/templates/containers.twig
+++ b/php/templates/containers.twig
@@ -414,7 +414,7 @@
                                         <input type="hidden" name="{{csrf.keys.value}}" value="{{csrf.value}}">
                                         <input class="button" type="submit" value="Submit" />
                                     </form>
-                                    You need to make sure that the timezone that you enter is valid. An example is <b>Europe/Berlin</b>. You can get valid values by looking at the 'TZ database name' column of this list: <a href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List"><b>click here<b/></a>.<br><br>
+                                    You need to make sure that the timezone that you enter is valid. An example is <b>Europe/Berlin</b>. You can get valid values by looking at the 'TZ database name' column of this list: <a href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List"><b>click here</b></a>.<br><br>
                                 {% else %}
                                     The timezone for Nextcloud is currently set to <b>{{ timezone }}</b>. You can reset the timezone again by clicking on the button below.<br><br/>
                                     <form method="POST" action="/api/configuration" class="xhr">