WhatsApp in-app browser breaks session during React signup verification flow

I’m developing a React + WhatsApp Business API + OpenAI web application, similar to Memorae.

The signup workflow is divided into four steps:

Email confirmation WhatsApp verification Calendar connection (Google / Microsoft – optional) Subscription plan selection

I’m facing an issue with step 2 (WhatsApp verification).

When a user enters their phone number and clicks the Verify button, they are redirected to WhatsApp, where a confirmation message is sent. The user then clicks the Back button after sending the message.

This Back button behavior is the problem.

I configured the button to redirect the user to the Step 3 URL. However, this opens the page inside the WhatsApp in-app browser on mobile. Since there is no session or cache available there, the user is redirected to the login page instead of continuing the signup flow.

Could you please review this workflow and suggest how I can return the user back to Chrome or Safari on mobile after WhatsApp verification?