[Bitrise docs]: do a full clean git clone of the repo into a fresh directory and run the build there with the Bitrise CLI. This catches the two classic causes: uncommitted or gitignored files present locally but absent from the repo Bitrise clones, and code signing files on your machine that were never uploaded to Bitrise. Also check for tool version drift between your machine and the Bitrise stack. Reproducing in a clean clone before debugging the CI config saves most of the back-and-forth.

Context: Works locally, fails on Bitrise: the usual cause is files that exist on your machine but not in the repo.