Profinet Error (PNIO0007): The Profinet output length '...' of device '...' exceeds the maximum number of bytes '...'.

Update the library/device description file of the device mentioned in the error message. Contact the device manufacturer to get the latest library/device description file.

Proceed as follows:

For Phoenix Contact devices, replace the existing device library by the updated library.
For devices of other manufacturers, import the GSDML file as described in section "Add devices by importing device description files (*.GSDML)" in the topic "Offline: Add Devices manually to PLANT".