Workflows on public repositories not working

[doanac]

I've been able to get this working for testing pull requests on a private repository. However, the same thing doesn't work on a public repository. I believe it may be due to this message from the the EC2 instance launched to process the action:

[2024-08-28 21:32:43Z ERR  GitHubActionsService] GET request to https://pipelinesghubeus22.actions.githubusercontent.com/yeUpnz3L1rGr0q5Pg3xqFjCluSlZKi4UcV4VOs5WLFqpaEQ0ws/_apis/distributedtask/pools/1/messages?sessionId=3e4dcffc-7ea0-4df5-b616-fe46379d3dc6&status=Online&runnerVersion=2.319.1&os=Linux&architecture=X64&disableUpdate=false failed. HTTP Status: Forbidden

Any ideas what might be going wrong?

NOTE: this is a PR based on a branch inside the public repository. I'm also trying to understand if there's a safe way to do PRs on public repositories from forked branches - perhaps some "ok-to-test" label or something?