Randstad VMS Configuration Analyst interview questions

After an initial phone screen interview with the internal recruiter, I was added to the hiring manager's calendar for the next day. That's how well the interview went. My skills and experience were well match with the role and the hiring manager agreed. However, I was surprised when I was ghosted and did not get a reply on my follow up email to Randstad 's recruiter (no feedback or update). This act was unprofessional especially for a recruiting firm.