CAN IO modules went into error and could not be reset by CANIO_STATUS.4 = 1. After some tests, the customer found the issue was as follows:

It was solved by providing isolation for Trio and Can IO module from the panel.

Also used separate 24V supply for Trio can and IO module supply .

The panel earthing was the issue, despite the voltage difference was less than 3V.

This issue was a rare one faced for this OEM as they have more than 100+ Trio machines running without a problem.