Typo.

configuration/sample-development.engine.ini

@@ -33,7 +33,7 @@ from_mail="monitoring@aura.engine"
 # The beginning of the subject. With that you can easily apply filter rules using a mail client
 mailsubject_prefix="[Aura Engine]"
 # Server where heartbeat info is sent to
-hearbeat_server = '127.0.0.1'   
+heartbeat_server = "127.0.0.1"   
 # Some UDP port
 heartbeat_port = 43334 
 # Seconds how often the vitality of the Engine should be checked (0 = disabled)

configuration/sample-docker.engine.ini

@@ -33,7 +33,7 @@ from_mail="monitoring@aura.engine"
 # The beginning of the subject. With that you can easily apply filter rules using a mail client
 mailsubject_prefix="[Aura Engine]"
 # Server where heartbeat info is sent to
-hearbeat_server = '172.17.0.1'   
+heartbeat_server = "127.0.0.1"
 # Some UDP port
 heartbeat_port = 43334 
 # Seconds how often the vitality of the Engine should be checked (0 = disabled)

configuration/sample-production.engine.ini

@@ -33,7 +33,7 @@ from_mail="monitoring@aura.engine"
 # The beginning of the subject. With that you can easily apply filter rules using a mail client
 mailsubject_prefix="[Aura Engine]"
 # Server where heartbeat info is sent to
-hearbeat_server = '127.0.0.1'   
+heartbeat_server = "127.0.0.1"
 # Some UDP port
 heartbeat_port = 43334 
 # Seconds how often the vitality of the Engine should be checked (0 = disabled)