diff --git a/simple_backup/simple_backup.py b/simple_backup/simple_backup.py
index 78a56be..f996878 100755
--- a/simple_backup/simple_backup.py
+++ b/simple_backup/simple_backup.py
@@ -375,12 +375,18 @@ class Backup:
 
             return ssh
         except UserWarning:
-            k = input(
-                f'Unknown key for host {self.ssh_host}. Continue anyway? (Y/N) ')
+            try:
+                k = input(
+                    f'Unknown key for host {self.ssh_host}. Continue anyway? (Y/N) ')
+            except EOFError:
+                # No terminal available (e.g. cron or systemd)
+                k = ''
 
-            if k[0].upper() == 'Y':
+            if k.strip().upper().startswith('Y'):
                 ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
             else:
+                logger.critical('Unknown host key for %s. Connection aborted', self.ssh_host)
+
                 return None
         except paramiko.BadHostKeyException as e:
             logger.critical('Can\'t connect to the server.')