I have a similar problem

A setup with one PLC (1212C) with 4 ProfiNet devices attached (Servo drives) working OK.

Changed to another PLC (1214C) with the same 4 devices, now assigned to new PLC. Old PLC disconnected.

Hardware and software configuration downloaded separately.

All can be detected in "Accessible devices" with correct IP-adresses and ProfiNet names.

But going Online says all four devices are "Not reachable", saying ProfiNet Connection parameters wrong.

Help much appreciated...

More info:

Error when going online or starting the PLC:

Error: IO device failure - PNIO configuration error (connection parameter) HW_ID= 271

Incoming event

This is the same, also loading older projects using the same PLC and devices.

Same outcome even with Antivirus and Firewall disabled on TIA-PC.

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Split from Can see Profinet slave but not reachable online.

Problem solved

The "Era of Miracles" has not yet ended...

A boot of the pc (Windows 10) and subsequent (of course) restart of TIA (14.1) rectified the network settings.

OBSERVE: with 2 plc's :

assigning devices to plc2

removing connections from plc1

stopping plc1

will NOT remove the device connections from plc1 and will lead to plc2 failure.

Disconnect plc1 to finallly be able to connect device to plc2 without errors.