diff --git a/prometheus-client.cabal b/prometheus-client.cabal
--- a/prometheus-client.cabal
+++ b/prometheus-client.cabal
@@ -1,5 +1,5 @@
 name:                prometheus-client
-version:             1.1.0
+version:             1.1.1
 synopsis:            Haskell client library for http://prometheus.io.
 description:         Haskell client library for http://prometheus.io.
 homepage:            https://github.com/fimad/prometheus-haskell
diff --git a/src/Prometheus/MonadMonitor.hs b/src/Prometheus/MonadMonitor.hs
--- a/src/Prometheus/MonadMonitor.hs
+++ b/src/Prometheus/MonadMonitor.hs
@@ -14,7 +14,6 @@
 import Control.Monad.Identity (Identity, runIdentity)
 import Control.Monad.Trans.Class
 import Control.Monad.Trans.Class (MonadTrans)
-import Control.Monad.Trans.Error (ErrorT, Error)
 import Control.Monad.Trans.Except (ExceptT)
 import Control.Monad.Trans.Identity (IdentityT)
 import Control.Monad.Trans.Maybe (MaybeT)
@@ -39,7 +38,6 @@
 instance MonadMonitor IO where
     doIO = id
 
-instance (Error e, MonadMonitor m) => MonadMonitor (ErrorT e m)
 instance (MonadMonitor m) => MonadMonitor (ExceptT e m)
 instance (MonadMonitor m) => MonadMonitor (IdentityT m)
 instance (MonadMonitor m) => MonadMonitor (MaybeT m)