This error is common when you install a new plugin. The plugin is blocked because in the settings you have not allowed unconfirmed plugins to work. The ways to unlock the Blocked Sketchup plugin are very simple as follows:
- Step 1: Window ->Extension Manager
- Step 2: Extension Setting
- Step 3: Approve Unidentified Extensions
Step 1: Enter Window ->Extension Manager

Step 2: Extension Setting
By clicking on the gear icon on the upper right.

Step 3: Approve Unidentified Extensions
Press Confirm

Result
All blocked plugins have been opened.
