Zend certified PHP/Magento developer

Magento custom session getting destroyed after user is redirected to other site

I am doing a Stripe integration on Magento site where customer can directly pay from My Account section. For success page, I am having is the success URL which stripe redirects customer too. I want the page to open only once. To implement one time page open, I am planning to implement custom customer session. However, when the user is redirected back from stripe to site, The custom session is not visible/destroyed. Below is the code

Create Custom Session

$this->_customerSession->setTransactionStatus('546464646');

If I read the $_SESSION on same page, the session Transaction Status is shown set. However, when I am redirected to the site, I don’t see the session.

I am trying to retrieve session using

$this->_customerSession->getTransactionStatus();

Can someone let me know why the session is no longer available when customer redirects back to site? Also, what can be the potential solution to this?