@AlinaMiko
You'll probably need to share some specifics (like why you needed to perform a factory reset, and any other changes you may have made) in order for community members to offer suggestions.
Or you could try contacting Support:
1. Go to https://support.google.com/googlenest/gethelp.
2. Select a category/product family, and type in a brief description of the issue, then click "Next".
3. Click "Other", then click "Next step".
4. Under "Resources", just click "Next step". (Clicking one of the listed links will bring up a Help page.)
5. Under "Contact options", choose to get a phone call or chat with the team, depending on availability in your country.
