If you see errors in SM under the Errors tab, you might also see a link there that says: Click here for more information.
When you click the link, it will take you to the Software Management Troubleshooting Guide that lists SM error messages with their meaning, cause and troubleshooting steps to resolve.
Here is the link to that Guide:
https://helpdesk.kaseya.com/hc/en-gb/articles/4409291501329
We have also compiled a list of error codes that might not have been mentioned in the above article: