Hi Marcelo,
It would be very helpful to check if any error messages are recorded in apache’s error_log (and possibly php’s error log, if there is such a separate log).
Also, if mod_security is involved, it should have recorded to the logfile which rule has blocked the request. Another possible interference of mod_security could be any URL normalization rules.
What really puzzles me is the fact that the plugin does not perform any special operation when activated/deactivated or when the admin panel is generated. Everything is within the “specs”.
It’s been a while since the last time I used mod_security. If I can find enough free time, I’ll test it. Which ruleset do you use? CRS?
Even if activation works, the license selection dialog of v1.5.1 might still fail due to possible URL normalizations. v1.5.2 should have any problems. I’d be very interested in your feedback about this.
Kind Regards,
George