There are two possible scenarios for that:
1) Incompatible versions
A common reason for the editor not to work is that you have a different version of the Editor and the Portal.
Both versions should be the same in order for the editor to communicate with the server correctly.
From Newired 19.2, the editor is able to identify when you are using different versions. When this is the case, after you log in to the editor, you will see a warning indicating the incompatibility of the versions:
In the above case, you need to update your Portal version. Please check the Update articles.
In case you need to upgrade the Editor, simply go to the Portal and download the latest editor version from there. Make sure you uninstall or replace the previous version. For more details, please check this article.
2) Client Unknown
This issue is quite rare, but if you come across it, you'll see the following error message on the editor:
This issue is caused by a Newired file you need to delete.
- On Windows:
In the folder C:\Users\<user>\AppData\Roaming\Newired Editor, delete this file: userSettings.json.
In the folder main ▸ Users ▸ <your user> ▸ Library ▸ Application Support ▸ Newired Editor, delete this file: userSettings.json.