Can you confirm the InDesign version you are using? Is it 2018.1 or 2018?
I assume the path to which you are trying to export the PNG is /Volumes/Shares/011 Changed Information/002 Changed Information/00617 Changed Information/Changed/ ?
Is this drive mounted via SMB?
Is it a NAS server?
An error occurred while saving the commentCarl Forde commented
I'm using InDesign 15.1.1 and am experiencing this problem exporting JPGs and PNGs to network drive. Export of PDF to the same location works fine.
This is on MacOS Catalina 10.15.6