Syncthing folders?

I run syncthing and would like to add a folder to sync with another syncthing on another server.
I created on umbrel debian server a folder called /mydata.

I get this error:
2022-06-02 12:37:14: Loading ignores: lstat /mydata/.stignore: permission denied

2022-06-02 12:37:14: Failed to create folder marker: stat /mydata/.stfolder: permission denied

2022-06-02 12:37:14: Error on folder yqxk2-ybnzm: stat /mydata/.stfolder: permission denied

How do you add a folder to sync?

Thank you.

The “folder ID” has to be the same across all devices, as it is the unique identifier of the folder.
Best practice is to keep the auto-generated ID to avoid conflicts with equally named folders on other devices.
I have followed it this way and it works well