diff --git a/ethers/providers/jsonrpc/subscriptions.nim b/ethers/providers/jsonrpc/subscriptions.nim
index 9da7e36..64a8080 100644
--- a/ethers/providers/jsonrpc/subscriptions.nim
+++ b/ethers/providers/jsonrpc/subscriptions.nim
@@ -80,11 +80,8 @@ proc getCallback(subscriptions: JsonRpcSubscriptions,
                  id: JsonNode): ?SubscriptionCallback  {. raises:[].} =
   try:
     if not id.isNil and id in subscriptions.callbacks:
-      try:
-        return subscriptions.callbacks[id].some
-      except: discard
-  except KeyError:
-    return SubscriptionCallback.none
+      return subscriptions.callbacks[id].some
+  except: discard
 
 # Web sockets
 
@@ -128,8 +125,8 @@ method subscribeLogs(subscriptions: WebSocketSubscriptions,
       onLog(failure(Log, error.toErr(SubscriptionError)))
       return
 
-    if log =? Log.fromJson(arguments{"result"}):
-      onLog(success(log))
+    let res = Log.fromJson(arguments{"result"}).mapFailure(SubscriptionError)
+    onLog(res)
 
   let id = await subscriptions.client.eth_subscribe("logs", filter)
   subscriptions.callbacks[id] = callback
@@ -269,13 +266,13 @@ method subscribeLogs(subscriptions: PollingSubscriptions,
                     Future[JsonNode]
                     {.async.} =
 
-  proc callback(id: JsonNode, changeResult: ?!JsonNode) =
-    without change =? changeResult, error:
+  proc callback(id: JsonNode, argumentsResult: ?!JsonNode) =
+    without arguments =? argumentsResult, error:
       onLog(failure(Log, error.toErr(SubscriptionError)))
       return
 
-    if log =? Log.fromJson(change):
-      onLog(success(log))
+    let res = Log.fromJson(arguments).mapFailure(SubscriptionError)
+    onLog(res)
 
   let id = await subscriptions.client.eth_newFilter(filter)
   subscriptions.callbacks[id] = callback
diff --git a/testmodule/providers/jsonrpc/rpc_mock.nim b/testmodule/providers/jsonrpc/rpc_mock.nim
index 41d5491..4abdb6e 100644
--- a/testmodule/providers/jsonrpc/rpc_mock.nim
+++ b/testmodule/providers/jsonrpc/rpc_mock.nim
@@ -9,11 +9,12 @@ import pkg/json_rpc/errors
 
 type MockRpcHttpServer* = ref object
   filters*: seq[string]
+  nextGetChangesReturnsError*: bool
   srv: RpcHttpServer
 
 proc new*(_: type MockRpcHttpServer): MockRpcHttpServer =
   let srv = newRpcHttpServer(["127.0.0.1:0"])
-  MockRpcHttpServer(filters: @[], srv: srv)
+  MockRpcHttpServer(filters: @[], srv: srv, nextGetChangesReturnsError: false)
 
 proc invalidateFilter*(server: MockRpcHttpServer, jsonId: JsonNode) =
   server.filters.keepItIf it != jsonId.getStr
@@ -30,6 +31,9 @@ proc start*(server: MockRpcHttpServer) =
     return filterId
 
   server.srv.router.rpc("eth_getFilterChanges") do(id: string) -> seq[string]:
+    if server.nextGetChangesReturnsError:
+          raise (ref ApplicationError)(code: -32000, msg: "unknown error")
+
     if id notin server.filters:
       raise (ref ApplicationError)(code: -32000, msg: "filter not found")
 
diff --git a/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim b/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
index 91947d6..8f5867a 100644
--- a/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
+++ b/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
@@ -99,7 +99,7 @@ suite "HTTP polling subscriptions":
 
   subscriptionTests(subscriptions, client)
 
-suite "HTTP polling subscriptions - filter not found":
+suite "HTTP polling subscriptions - mock tests":
 
   var subscriptions: PollingSubscriptions
   var client: RpcHttpClient
@@ -193,3 +193,17 @@ suite "HTTP polling subscriptions - filter not found":
     await startServer()
 
     check eventually subscriptions.subscriptionMapping[id] != id
+
+  test "calls callback with failed result on error":
+    let filter = EventFilter(address: Address.example, topics: @[array[32, byte].example])
+    var failedResultReceived = false
+
+    proc handler(log: ?!Log) =
+      if log.isErr:
+        failedResultReceived = true
+
+    let id = await subscriptions.subscribeLogs(filter, handler)
+
+    await sleepAsync(50.milliseconds)
+    mockServer.nextGetChangesReturnsError = true
+    check eventually failedResultReceived
diff --git a/testmodule/testContracts.nim b/testmodule/testContracts.nim
index 6c81f2c..53e2547 100644
--- a/testmodule/testContracts.nim
+++ b/testmodule/testContracts.nim
@@ -150,8 +150,10 @@ for url in ["ws://"  & providerUrl, "http://"  & providerUrl]:
       var transfers: seq[Transfer]
 
       proc handleTransfer(transferRes: ?!Transfer) =
-        if transfer =? transferRes:
-          transfers.add(transfer)
+        without transfer =? transferRes, error:
+          echo error.msg
+
+        transfers.add(transfer)
 
       let signer0 = provider.getSigner(accounts[0])
       let signer1 = provider.getSigner(accounts[1])