The ecommerce e2e tests cannot be run locally against the devstack firefox container.
Here is a WIP starter PR with some notes around the problem: https://github.com/edx/ecommerce/pull/2389/files
I am hoping I can get away with just testing some e2e changes using the branch configuration for the Jenkins job https://tools-edx-jenkins.edx.org/job/e2e/job/stage-ecommerce/ . If that works out, I have a workaround. Otherwise, this would be a blocker.