This means you're missing templates.
I've reinstalled Traccar again and I have the default templates, the issue remains.
But when I put the old templates and the issue remains too.
Why would you put old templates?
I used it only to test.
But with a clean installation of Traccar (only with traccar.xml from the previous version) I have the same issue.
Since I updated to the 6.10 version, the web and telegrams notificacions only shows this text: (***)
Even after reinstalling version 6.10 without any modifications to the templates, the same text appears.
What is the problem?