Did you forgot to add some rules into your .gitignore and committed some files by mistake? Here is how to fix that. Be aware that this procedure is going to overwrite the entire history of the project and your collaborators will have to clone the repository again.
Fix .gitignore files and commit
Fix your .gitignore files. You can have more than one, by placing them into different folders (useful for projects using different programming languages). Use https://gitignore.io to generate good defaults.