1.  Without offering any reference from your previous employer/ manager:
Yes, in many of the job interviewing process, there are few candidates who refer their past managers or employers information in their resume along with their contact details. But in some cases, many interviewees will not refer any of their past managers or employers details in their resume, which eventually make their potential employers wonder, why you [candidate] didn’t mention any reference details of your past managers or employers and also they might think you are hiding something very serious regarding your past performances under your previous employers or managers.

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They might also think you are avoiding them from talking to your previous managers. So, give all the information to the recruiter from your side, so that you won’t be stuck in your career perspective.
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