CompTIA Network+ (N10-009) N10-009 — Question 567

A customer migrates its phone system from analog to a new hosted VoIP/software application solution with integrated video. After installation, some users notice issues with dropped calls, broken video, and slow internet access. The issues start in the mid-morning and continue into the afternoon. However, remote users do not report the same issues. Which of the following is the most likely cause of the issues?