Synchronization error in operating system due to incorrect data

We have a S7-400H(414H) system running 11 years and yesterday we have a problem with that system and need your help

The Standby CPU suddenly changed to ERROR-SEARCH & STOP mode. The LED on synch module of both CPU are normal at once, the system can't be reestablished and switch to redundant mode.

We try to replace both Syn module IFM1F of both CPU and optic cable. But cannot solve problem, the IFM1F LED on both CPU still are RED

We already tried to Power off, Reset memory and replaced a new Memory card of Standby CPU but problem still exist.

After that, we have replaced a new Standby CPU but problem still persists

Please see

1.the diagnostic buffer as attached for your info.

2. The Standby CPU go to STOP mode

3. We have replaced Syn module, optic cable, Memory card and even new CPU but problem cannot be solved

Hello,

CPU diagnostic buffer wasn't shared.