Hi Mouradm,

The biggest problem with recommendations is that, most often, individuals select people who can't respond fully. In order for your letters to be as effective as possible, you should look at engaging only effective recommenders. Selecting a recommender whose letter is ineffective or who appears dubious about your qualifications may raise doubts about your rest of your application. If this person can represent you well in the letters then no harm. However ideally you should try to get recommendations from someone you have worked for a significant time or have worked closely with.
https://futureworks.co.in/knowledgecente ... mmendation this article will guide you on how to choose recommenders.