1 files changed, 8 insertions, 1 deletions

diff --git a/README.md b/README.md
index 2e956d2..fd4f4e1 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,9 @@
-# ejabberd-metrics
+## ejabberd-tools
 
+### error codes
+Lookup table for all custom error codes.
+The potential reasons are sorted by probability of being the root cause.
+
+| code | potential reason |
+| :---: | :---|
+| 17 | login credential mismatch, potential api permission problem |