Hi!

    I have just installed Debian 9 and, following the wiki, tried to install 
tinity, but when I run apt-get update (or apt update), I get:

----
Err:8 http://mirror.xcer.cz/trinity-sb stretch/deps-r14 Sources
  403  Forbidden

[...]

Reading package lists... Done
W: The repository 'http://mirror.xcer.cz/trinity-sb stretch Release' does not 
have a Release file.
N: Data from such a repository can't be authenticated and is therefore 
potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration 
details.
E: Failed to fetch 
http://mirror.xcer.cz/trinity-sb/dists/stretch/deps-r14/source/Sources  403  
Forbidden
E: Some index files failed to download. They have been ignored, or old ones 
used instead.
----

    I tried to access to http://mirror.xcer.cz/trinity-sb with firefox, and I 
get a "Forbidden" error. 

    Are there any mirrors I can use? 

Thanks in advance,
 -- Diego.