The enemies are not attacking the base or sending raids. They are just standing still and defending the hives. All enemy settings are standard (default). The Lignumis mod is enabled, and this planet is the starting one. The enemies were active here. But on Nauvis, everything is calm. How can this be fixed?

I don't know. It's likely caused by another mod. The last time I saw an issue with enemy not attacking was with Lignumis too. But it's for multiplayer.

Do you have mods that modify planet properties?

I can take a look if you post your save.

Thank you for your response!
Here is the link to the savefile(https://drive.google.com/file/d/11-3xm7jT6UB3cHXPU4SE0SM73-CyQYaA/view?usp=sharing). I hope this helps)

Thanks. There is an issue on selecting planet to attack under certain scenarios.

It'll be fix next version. Treat your Nauvis as having peaceful truce in the mean time lol.