diff --git a/packages/frontend/src/components/steps/Step2.tsx b/packages/frontend/src/components/steps/Step2.tsx
index c62ca04..4e36750 100644
--- a/packages/frontend/src/components/steps/Step2.tsx
+++ b/packages/frontend/src/components/steps/Step2.tsx
@@ -12,7 +12,6 @@ import { Job } from 'bull'
 import {
   ContractTransactionReceipt,
   ContractTransactionResponse,
-  EventLog,
   hexlify,
   Interface,
   parseUnits,
diff --git a/packages/frontend/src/hooks/useExecutorService.test.ts b/packages/frontend/src/hooks/useExecutorService.test.ts
index e009991..3458e4e 100644
--- a/packages/frontend/src/hooks/useExecutorService.test.ts
+++ b/packages/frontend/src/hooks/useExecutorService.test.ts
@@ -1,4 +1,5 @@
 import { renderHook, waitFor } from '@testing-library/react'
+import axios from 'axios'
 import EventSourceMock, { sources } from 'eventsourcemock'
 import { vi } from 'vitest'
 
@@ -6,7 +7,7 @@ import useExecutorService, {
   ExecuteDto,
   TracingOptions,
 } from './useExecutorService'
-import axios from 'axios'
+import { ExecuteError, ExecuteProcessorError } from '../types'
 
 const validExecuteDtoMock: ExecuteDto = {
   logIndexes: [],
@@ -145,6 +146,10 @@ describe('observeExecutorServiceJob', () => {
   })
 
   it('should error() when eventsource sends error event', async () => {
+    const errorMock: ExecuteError = {
+      type: ExecuteProcessorError.CERTIFICATE_NOT_FOUND,
+      message: 'message',
+    }
     const { result } = renderHook(() => useExecutorService())
 
     await waitFor(() => {
@@ -158,13 +163,13 @@ describe('observeExecutorServiceJob', () => {
       )
       observable.subscribe({
         error: (error) => {
-          expect(error).toBe('"any error"')
+          expect(error).toBe(errorMock.message)
         },
       })
 
       sources[
         `${import.meta.env.VITE_EXECUTOR_SERVICE_ENDPOINT}/v1/job/subscribe/1`
-      ].emitError('any error')
+      ].emitError({ data: JSON.stringify(errorMock) })
     }
   })
 })
diff --git a/packages/frontend/src/hooks/useExecutorService.ts b/packages/frontend/src/hooks/useExecutorService.ts
index 17c7201..f70b94a 100644
--- a/packages/frontend/src/hooks/useExecutorService.ts
+++ b/packages/frontend/src/hooks/useExecutorService.ts
@@ -1,11 +1,19 @@
+import * as ERC20MessagingJSON from '@topos-protocol/topos-smart-contracts/artifacts/contracts/examples/ERC20Messaging.sol/ERC20Messaging.json'
+import * as BurnableMintableCappedERC20JSON from '@topos-protocol/topos-smart-contracts/artifacts/contracts/topos-core/BurnableMintableCappedERC20.sol/BurnableMintableCappedERC20.json'
 import axios from 'axios'
 import { Job, JobId } from 'bull'
+import { OAuthResponse } from 'common'
+import { Interface } from 'ethers'
 import { EventSourcePolyfill } from 'event-source-polyfill'
 import { useContext, useEffect, useMemo, useState } from 'react'
 import { Observable } from 'rxjs'
 
-import { OAuthResponse } from 'common'
 import { ErrorsContext } from '../contexts/errors'
+import {
+  ExecuteError,
+  ExecuteProcessorError,
+  ExecuteTransactionError,
+} from '../types'
 
 export interface ExecuteDto {
   logIndexes: number[]
@@ -106,11 +114,53 @@ export default function useExecutorService() {
             }
           }
 
-          eventSource.onerror = (error: any) => {
-            const message = error.data || JSON.stringify(error)
-            console.error(message)
-            eventSource.close()
-            subscriber.error(message)
+          eventSource.onerror = ({ data }: any) => {
+            try {
+              const executeError: ExecuteError = JSON.parse(data)
+              let { message } = executeError
+
+              if (
+                executeError.type ===
+                ExecuteProcessorError.EXECUTE_TRANSACTION_REVERT
+              ) {
+                const executeTransactionError: ExecuteTransactionError =
+                  JSON.parse(executeError.message)
+
+                if (!executeTransactionError.decoded) {
+                  const ERC20MessagingInterface = new Interface(
+                    ERC20MessagingJSON.abi
+                  )
+                  const ERC20Interface = new Interface(
+                    BurnableMintableCappedERC20JSON.abi
+                  )
+
+                  const decodedError =
+                    ERC20MessagingInterface.parseError(
+                      executeTransactionError.data
+                    ) || ERC20Interface.parseError(executeTransactionError.data)
+
+                  message = JSON.stringify({
+                    type: ExecuteProcessorError.EXECUTE_TRANSACTION_REVERT,
+                    message: decodedError?.name,
+                  })
+                } else {
+                  message = JSON.stringify({
+                    type: ExecuteProcessorError.EXECUTE_TRANSACTION_REVERT,
+                    message: executeTransactionError.data,
+                  })
+                }
+              } else {
+                message = executeError.message
+              }
+
+              console.error(message)
+              eventSource.close()
+              subscriber.error(message)
+            } catch (error) {
+              console.error(error)
+              eventSource.close()
+              subscriber.error(error)
+            }
           }
         })
       }
diff --git a/packages/frontend/src/types.ts b/packages/frontend/src/types.ts
index c9f31da..03c01e2 100644
--- a/packages/frontend/src/types.ts
+++ b/packages/frontend/src/types.ts
@@ -21,3 +21,23 @@ export interface FetchData<T> {
   error?: Error
   loading?: boolean
 }
+
+export enum ExecuteProcessorError {
+  PROVIDER_INVALID_ENDPOINT = 'PROVIDER_INVALID_ENDPOINT',
+  CONTRACT_INVALID_ADDRESS = 'CONTRACT_INVALID_ADDRESS',
+  CONTRACT_INVALID_NO_CODE = 'CONTRACT_INVALID_NO_CODE',
+  WALLET_INVALID_PRIVATE_KEY = 'WALLET_INVALID_PRIVATE_KEY',
+  CERTIFICATE_NOT_FOUND = 'CERTIFICATE_NOT_FOUND',
+  EXECUTE_TRANSACTION_FAILED_INIT = 'EXECUTE_TRANSACTION_FAILED_INIT',
+  EXECUTE_TRANSACTION_REVERT = 'EXECUTE_TRANSACTION_REVERT',
+}
+
+export interface ExecuteError {
+  type: ExecuteProcessorError
+  message: string
+}
+
+export interface ExecuteTransactionError {
+  decoded?: boolean
+  data: string
+}