Class 'Stripe\Checkout\Session' not found

Hello,
Sorry for my english.

I have a problem on a new installation.
Event booking 3.17.6
os_stripecheckout 3.17.1 payment plugin

When I want to make a payment, I have this error message:
Class 'Stripe \ Checkout \ Session' not found

Do you have an idea ?

Thank you.

 

I think it is because the payment plugin was not installed properly. Please submit a support ticket sending us super admin account of your site so that I can check and get it installed properly for you

Regards,

Tuan