1769-L30ERMS Fault

Hey folks, I get an occassional fault on the PLC. Here's the message I get in the Major Faults tab:

(Type 03) I/O Fault
(Code 23) At least one required connection not established before going into RUN mode

What is this error and how do I solve it. This PLC runs normally for months with no issue.

Are there any yellow triangles in your I/O tree?

https://literature.rockwellautomation.com/idc/groups/literature/documents/rn/1768-rn015_-en-e.pdf

its mentioned as an occasional fault due to timing of the io connections not being made to modules marked as required,