diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# hpqtypes-1.10.0.1 (2022-09-23)
+* Provide detailed error when `openConnection` fails.
+
 # hpqtypes-1.10.0.0 (2022-09-14)
 * Improve `Show` instances of `HPQTypesError` and `LibPQError`.
 * Remove `INLINE` and `INLINABLE` pragmas.
diff --git a/hpqtypes.cabal b/hpqtypes.cabal
--- a/hpqtypes.cabal
+++ b/hpqtypes.cabal
@@ -1,5 +1,5 @@
 name:                hpqtypes
-version:             1.10.0.0
+version:             1.10.0.1
 synopsis:            Haskell bindings to libpqtypes
 
 description:         Efficient and easy-to-use bindings to (slightly modified)
diff --git a/src/Database/PostgreSQL/PQTypes/Internal/Connection.hs b/src/Database/PostgreSQL/PQTypes/Internal/Connection.hs
--- a/src/Database/PostgreSQL/PQTypes/Internal/Connection.hs
+++ b/src/Database/PostgreSQL/PQTypes/Internal/Connection.hs
@@ -216,7 +216,10 @@
         if | ps == c_PGRES_POLLING_READING -> (threadWaitRead  =<< getFd conn) >> loop
            | ps == c_PGRES_POLLING_WRITING -> (threadWaitWrite =<< getFd conn) >> loop
            | ps == c_PGRES_POLLING_OK      -> return conn
-           | otherwise                     -> throwError "openConnection failed"
+           | otherwise                     -> do
+               merr <- c_PQerrorMessage conn >>= safePeekCString
+               let reason = maybe "" (\err -> ": " <> err) merr
+               throwError $ "openConnection failed" <> reason
       where
         getFd conn = do
           fd <- c_PQsocket conn