Cant go online with my PLC: Difference in lower level component

I cant go online with my PLC, i have a ET200 SP (6ES7512-1DK01-0AB0).

I have diffrents signs that shows up that says: Difference in lower level component

what could the problem be?

Hi,

You've different programs on ONLINE / OFFLINE.

Click on PLC -> mouse left button -> Compare Online/Offline.  

Options from now:

If you click on DOWNLOAD TO DEVICE  > Your offline program will be downloaded and the software will match (with a green round)

If you click on UPLOAD TO DEVICE -> You recover the Online program.  But pay attention S7-1200 that you're working, maybe not give you this option.

Otherwise, if you deploy Program Blocks >> Inside, you could realise with blocks are equal or different between online / offline.