Can't send a message to the background script.

[ISolveStuff]

When trying to send any kind of data to the background script, I always get this error:
Am I missing something?

index.global.js:30 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'fingerprint')
    at index.global.js:30:19346
    at i (index.global.js:30:3325)
    at index.global.js:30:4636
    at new Promise (<anonymous>)
    at sendMessage (index.global.js:30:4425)
    at n (index.global.js:40:2141)
    at index.global.js:43:427
    at index.global.js:18:11550
    at ft (index.global.js:18:1494)
    at Le (index.global.js:18:1564)

Content:

import { sendMessage } from 'webext-bridge/background'
await sendMessage('test', 'hey', 'background')

Background:

onMessage('test', ({ data }) => {
  console.log(data)
  return { message: 'Received data' }
})

shim.d.ts

import type { ProtocolWithReturn } from 'webext-bridge'

declare module 'webext-bridge' {
  export interface ProtocolMap {
    // define message protocol types
    // see https://github.com/antfu/webext-bridge#type-safe-protocols
    'test': ProtocolWithReturn<string, { message?: string }>
  }
}

[ISolveStuff]

I found the solution: serversideup/webext-bridge#57