Error while LetsEncrypt Plugin start

Hey Guys,

when i click on start at the LetsEncrypt Plugin i become following errors:
http://pastebin.com/J8WKKTZD

Can help me somebody?

IMSCP Version: 1.3.7
LetsEncrypt Version: 2.0.5

I use Debian 8.7 Jessie, LetsEncrypt Version: 2.0.5; I-MSCP Version 1.3.16;

Modules:Plugin_LetsEncrypt.log: http://pastebin.com/Zi3YuReh

I click on the start Button and in the status field is the following Error: pastebin.com/J8WKKTZD
The Log of the Plugin is above