A network engineer connects a business to a new ISP. A simple ping test to 8.8.8.8 is successful. However, users complain of extreme slowness to any website and periods of no connectivity. Which of the following is the most likely cause?

A VLAN mismatch would typically cause connectivity issues for devices within the same VLAN or prevent them from accessing resources on different VLANs. However, this scenario does not explain the successful ping to 8.8.8.8, which indicates that at least some network traffic is being routed correctly, unlike what would happen with a VLAN issue.

While an incorrect subnet mask can lead to local network issues, it is less likely to cause the symptoms described. A misconfigured subnet mask might limit communication within a local network segment, but if devices can still ping external IPs like 8.8.8.8, the subnet mask is likely not the primary cause of slowness or connectivity drops.

A duplicate ISP IP address would result in significant connectivity issues or complete inability to access the internet. However, since users can successfully ping 8.8.8.8, it suggests that the IP address conflict is not present, or the issue is intermittent, which would not fit the symptoms described.