Bad Token, You seem to have followed an invalid link

duplicate of #512818: Flag: "Bad token" message

I just installed the flag module and when I click on any flag link I get the next error message:

"Bad token. You seem to have followed an invalid link."

and an access denied.

How can I fix it? Is it something I forgot to configure? Does it has to be with the Token Module?

thanks in advance

No idea -- is there any more detail in the log? can you debug?

Yes, I am debug but not found any errors in log.

You'll need to debug the code that checks the token on the link.

Ok, I will try.

I have this too.
I am using the flag field it in a panelizer.

Hi,
This is to inform you that when we tried to debug the code as per the instructions given by your end, we found that we get tokens. But when we try to get that token at flag.page.inc, it gets changed. This makes the former token invalid.
We also updated the Drupal version to the latest one. Still, the issue is not getting resolved.

Hi,
My issue has been resolved after updating php version 5.6 into 7.

Hi,
The issue has been resolved after updating php version 5.6 into 7.