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Hello. 
I have a test where I need to fill an iframe (Stripe payment iframe) where I enter credit card number,expiration date and cvc.  
My test works in following situations: 
1. Cypress on local and remote env
My test DOES NOT work in following situation:
2. Cypress as instance in gitlab CI/CD (gitlab runner) and the same remote env 

My code to access iframe 
        cy.get(".__PrivateStripeElement > iframe").within(function($iFrame){
            cy.wrap($iFrame.contents().find('body')).find('#Field-numberInput').type('4242').type('4242').type('4242').type('4242')
            cy.wrap($iFrame.contents().find('body')).find('#Field-expiryInput').type('12').type('34')
            cy.wrap($iFrame.contents().find('body')).find('#Field-cvcInput').type('123').type('{enter}')
        });