Can't connect to downstream switch although it's on and working.

Replaced a switch the other day that has a downstream switch with cameras attached.

The cameras went down and the cause was the ports were getting err disabled due to bpdu packets being detected on the ports on the new switch.

Quick work around I disabled bpduguard on the affected ports, shut/no shut and now the cameras are back up and working.

Problem is I need to get to the downstream switch and disable STP so I can enable bpduguard on the new switch again.

Can't ping the downstream switch from the new switch and it's not in the arp or Mac address tables even though the cameras that are connected to it are.

Super confused and trying to do this remotely as the downstream switch is 40 ft in the ceiling and would require a whole work order to get up there and connect via console.