diff --git a/lib/logic/api_maps/hetzner.dart b/lib/logic/api_maps/hetzner.dart
index 51833622..dc11d5aa 100644
--- a/lib/logic/api_maps/hetzner.dart
+++ b/lib/logic/api_maps/hetzner.dart
@@ -114,7 +114,8 @@ class HetznerApi extends ApiMap {
 
     final apiToken = StringGenerators.apiToken();
 
-    final hostname = domainName.split('.')[0];
+    // Replace all non-alphanumeric characters with an underscore
+    final hostname = domainName.split('.')[0].replaceAll(RegExp(r'[^a-zA-Z0-9]'), '_');
 
     /// add ssh key when you need it: e.g. "ssh_keys":["kherel"]
     /// check the branch name, it could be "development" or "master".