diff --git a/Troubleshooting-Mail.md b/Troubleshooting-Mail.md
index 27d1c0f..4c0fee9 100644
--- a/Troubleshooting-Mail.md
+++ b/Troubleshooting-Mail.md
@@ -2,6 +2,22 @@
 
 [Uberspace Email](https://github.com/wekan/wekan/issues/2009#issuecomment-1017630758)
 
+## On Premise internal network Email
+
+If you need to test receiving WeKan at On-Premise internal network,
+where is no access to Internet email services,
+for receiving email you can use for example this:
+
+https://github.com/maildev/maildev
+
+For example, have it running at your local network IP address, that you change here,
+to replace example IP address 192.168.0.200 with your maildev server IP address,
+and look at maildev settings, what is username and password:
+
+```
+MAIL_URL="smtp://username:password@192.168.0.200:25"
+```
+
 ## Newest Wekan
 
 In [Wekan v5.02](https://github.com/wekan/wekan/blob/main/CHANGELOG.md#v502-2021-03-02-wekan-release) is fix for STMP settings [that works with very happy feedback](https://github.com/wekan/wekan/issues/3529#issuecomment-789085999). It requires: