Add Homee diagnostics platform (#39427)

Co-authored-by: Robin Lintermann <robin.lintermann@explicatis.com>

source/_integrations/homee.markdown

@@ -15,6 +15,7 @@ ha_platforms:
   - button
   - climate
   - cover
+  - diagnostics
   - event
   - fan
   - light
@@ -62,6 +63,22 @@ New devices added to Homee will be automatically discovered after a restart of H
 
 Changed values are reported from Homee in defined time intervals and not always in realtime. For example, while a cover moves, the position is updated only every few seconds and intermediate states may be missed by Home Assistant.
 
+## Troubleshooting
+
+First, see the general [Home Assistant troubleshooting guide](/docs/configuration/troubleshooting/).
+
+The **homee** integration supports [debug logs and diagnostics](/docs/configuration/troubleshooting/#debug-logs-and-diagnostics).
+
+### Homee device not working as expected
+
+Make sure, the {% term device %} works as expected in homee.
+If a homee device shows up in Home Assistant, but does not work as expected or is missing {% term entities %}, open a [report](https://github.com/home-assistant/core/issues) and attach error logs and the device's {% term diagnostics %} data.
+
+### Integration not loading or homee device not showing up in HA
+
+Check that the homee-user, used for Home Assistant, is allowed to see the device.
+If that is the case, open a [report](https://github.com/home-assistant/core/issues) and attach error logs and the diagnostic data of the {% term integration %}.
+
 ## Reconfiguration
 
 This integration supports reconfiguration, allowing you to change the IP address, even after a device has already been set up.