Error getting region when creating an AWS monitor


I use Sitescope 11.20 and I try to create an AWS Monitor but when I want get Region, I obtain the following error : PKIX path building failed: unable to find valid certification path to requested target

I'm sure about my aws credentials and theirs privileges because I created this monitor few month ago so I don't understand why now  I obtain this error.

Do you have idea about this problem  ?