Get email notifying me of a forum topic but can't access thread

[pde-louraille]

From time to time, after getting an email that a post has been made on a forum, I get this message:
-----
An Error Has Occurred!
The topic or board you are looking for appears to be either missing or off limits to you.
-----

Today, it is the topic labelled: New Topic: HDR composition

Bug? Feature?

 

[Nocturnal]

Same here. I figure the topic was removed by the OP.