diff --git a/roles/matomo/README.adoc b/roles/matomo/README.adoc
index 4d7ca6589..0fdbb3a4d 100644
--- a/roles/matomo/README.adoc
+++ b/roles/matomo/README.adoc
@@ -39,6 +39,13 @@ _Finally, continue to https://download.iiab.io[install IIAB], e.g. by running `s
 
 Log in to your IIAB's full Matomo URL, e.g. http://box.lan/matomo, as arranged above.
 
+WARNING: If your IIAB URL is *not* http://box.lan, you may run into a big orange warning from Matomo that it has been configured to run from a different address. Here are the steps to fix this problem.
+
+1. Copy the IP address listed in the box below "How do I fix this problem and how do I log in again?" For example, I see 'trusted_hosts[] = "192.168.64.10"', so I copy "192.168.64.10".
+2. Run "sudo nano /library/www/matomo/config/config.ini.php" to edit Matomo's config file.
+3. Paste or type the IP address from Step 1 to replace "box.lan" in the trusted_hosts line, which should be about line 13. When I'm done, my line 13 says 'trusted_hosts[] = "192.168.64.10"' instead of 'trusted_hosts[] = "box.lan"'.
+4. Refresh the Matomo homepage and the warning should be gone.
+
 Take a look at Matomo's official guides to further set this up: https://matomo.org/guides/
 
 WARNING: Matomo won't show any traffic statistics until after 1 day or reboot (which are the events that trigger the log scraper!)