/schedule skill consistently fails to connect to remote scheduling service (Pro account)

Description

The /schedule skill has failed across every session for multiple days with the error:

"We're having trouble connecting with your remote claude.ai account to set up a scheduled task."

Account details

• Email: <redacted>
• Subscription: Pro (confirmed via claude auth status)
• Auth method: claude.ai (firstParty)

Environment

• Claude Code versions affected: v2.1.143 through v2.1.165
• OS: WSL2 (Ubuntu), Linux 6.6.114.1-microsoft-standard-WSL2

What was ruled out

• Auth is valid (loggedIn: true, authMethod: claude.ai, subscriptionType: pro)
• Network connectivity to claude.ai works fine (TLS handshake succeeds, 403 on raw GET as expected)
• Issue persists across multiple Claude Code restarts and VSCode/terminal session resets
• /feedback built-in tool also returns 403, suggesting a possible account-level API access issue

Steps to reproduce

1. Log in with a Pro claude.ai account
2. Run /schedule in Claude Code
3. Observe immediate connection error — no scheduling UI appears

Expected behaviour

/schedule opens the scheduling flow to create a remote scheduled agent.

Actual behaviour

Immediate error: "We're having trouble connecting with your remote claude.ai account to set up a scheduled task."