@Csiembida
Without any specifics (such as which device you are trying to set up and exactly what happens when you try), it's hard for anyone to offer suggestions in this forum. By the way, Google Nest dropped support for the "Nest Secure" alarm system indicated in your post on April 8, 2024.
You could try contacting Support instead:
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 page.)
5. Under "Contact options", choose to get a phone call or chat with the team, depending on availability in your country.
