Timestamp Problem

[julien zerbib]

Hello,

Since this week, I have this error on submiting a signature :
"Timestamp is too far in the future"

But my timestamp is built like this :
'timestamp' => gmdate( "Y-m-d\TH:i:s\Z" )

In order to get it work, i had to do this :
'timestamp' => gmdate( "Y-m-d\TH:i:s\Z", strtotime( '-1 min' ) )

Note that "strtotime( '-2 min' )" return the error :
"Timestamp is too far in the past"

If somebody can tell me why...

Thanks,

Ju'