For our professional lives we face challenges everyday and many times when these challenges exceed people ring the wrong bell. Being negative for this answer is the worst case scenario never includes less salary, work pressure, intolerable boss and something like that in your interview. This gives a negative experience to the hiring team and the employers.
The interviewer wants to know about you and your reliability. Internally whatever the problem you are facing in the job never let it show in your face. Give it a smile and be positive during the answer. This gives support to your values and help understanding the other person about your situation. The best you can do is including your manager in reference and tell the interviewer that you have the potential to work and achieve much better. The opportunities they are offering will help you to grow with fast pace and will enrich your skills.
Never include performance Issues during the answer this showcases that you are a weak contender for this job and they will surely like to hire someone better. If candidates include a positive reason for a job change then it increases their chances of getting selected. It makes sense that you left the job because you feel more challenges to work on but saying directly this to an employer is not a good idea. People who feel monotonous and must explain that they are looking to work on new projects and have confidence to provide much better than the current situation.