How do you approach debugging a complex codebase?

When debugging a complex codebase, my approach would be to first try to reproduce the issue by recreating the steps that led to the problem. Once I have a clear understanding of the problem, I would start by reviewing any error messages or logs that were generated. This could give me some clues about where the problem is located in the code. Next, I would use debugging tools such as breakpoints and print statements to narrow down the location of the problem. I would also use the process of elimination, by commenting out sections of code to see if that resolves the issue. I would also look into the documentation and do some research on similar issues and solutions. Finally, I would seek help from my team members and ask for their perspective on the issue.