Clerk Dev Mode: Unable to Redirect to Application

# Problem:

After a user signs in for the first time, Clerk successfully requests the user's email and then redirects them to create a username. This part works as expected. However, after the user creates their username, Clerk redirects to the development mode instance instead of redirecting back to my application.

## Expected Behavior:
After the user creates their username, Clerk should redirect the user to the specified URL in my application (e.g., the dashboard or home page).

## Current Behavior:
Instead of redirecting back to my application after username creation, Clerk is redirecting to the development mode instance.

**Steps to Reproduce**
1. Set up Clerk in a local development environment.
2. Go through the sign-in process with a new user.
3. After signing in, enter the required email and proceed to the username creation step.
4. After creating the username, observe the redirection behavior.

**Additional Context**
**Environment:**
- Local development
- Clerk SDK version: [Include Version]
- Framework: [e.g., Next.js, React, etc.]
- Browser: [e.g., Chrome, Firefox, etc.]

**Relevant Environment Variables:**
- `NEXT_PUBLIC_CLERK_FRONTEND_API`: [Your Frontend API Key]
- `CLERK_API_KEY`: [Your Backend API Key]
- `NEXT_PUBLIC_CLERK_AFTER_SIGN_UP_URL`: [Expected Redirect URL]