Eclipse Pro will show this alert when imported coils have a material code that has not been entered into the system. Eclipse Pro was unable to associate those coils with a material. If left uncorrected, it could mean that Pro will compute inaccurate inventory levels, which will in turn mean inaccurate predicted schedules and material delivery tasks (Warehouse App).
The solution depends on whether the material code in question is legit. If it is, then simply create an entry in the materials table in Eclipse Classic for this code. If it is not a correct code, then the coil import data will need to be corrected and reimported.