[Error]: signature does not match event payload and secret

Hi, just set up hookshot, tried to send 2 events but got errors. Should webhook secret be a random value or a secrete generated by GitHub app aka "client secrets"?

ERROR 00:34:46:245 [Webhooks] Failed handle GitHubEvent: AggregateError: 
    Error: [@octokit/webhooks] signature does not match event payload and secret
        at verifyAndReceive (/usr/bin/matrix-hookshot/node_modules/@octokit/webhooks/dist-node/index.js:259:19)
        at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
ERROR 00:37:50:204 [Webhooks] Failed handle GitHubEvent: AggregateError: 
    Error: [@octokit/webhooks] signature does not match event payload and secret
        at verifyAndReceive (/usr/bin/matrix-hookshot/node_modules/@octokit/webhooks/dist-node/index.js:259:19)
        at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

What should be the content type of the webhook(application/json or application/x-www-form-url-encoded)?

Do I need to specify room for registration? And if I do do I keep the exclamation mark, i.e. !yVrxYIBfoOPIdTwbEX ?

Can someone share their configs for GitHub please, the registration file for synapse and the registration/configuration for hookshot. I do not understand what I should be putting in url for registration configs.

Start with the GitHub webhook handling path identified in the report, especially @octokit/webhooks verifyAndReceive and the hookshot registration/configuration values. Check how the secret, content type, room, and registration URL are expected to be supplied; done means documenting or correcting the configuration so signed GitHub events are accepted.