ConversionXL LLC interview questions

The selection process is split into 4 parts: screening call, call with the hiring manager, call with the head of department, and test. I only had the first two, both of which had competency-based questions. The last call with the hiring manager went alright; I had a strong feeling I was getting the next interview. However, I was rejected the next day after the head of the department looked at my LinkedIn profile (I have no idea what he found there). No feedback was provided, which made me feel disappointed because it's a normal practice in the UK.