Hello

I have a big problem, many of my users tell me things like:

Failure to redirect

1 - It has happened several times that when I try to enter any forum post or in any section of it, throw me a screen that reads -----> THE FORUM IS SPECIFIED INVALIDO.SI you followed a valid link, please notify the administrator.
But if you then refresh the same page tells me that message, if you access requesting a beginning, and no failure has happened to me always in the same section or in the same post.

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THE FORUM IS SPECIFIED INVALIDO.SI you followed a valid link, please notify the administrator.

I recostruido forums and topics but the problem continues, someone knows that can be?

greetings and thanks