error extension stripe

I have a problem to connect my stripe with the stripe plugin 

My problem is when I create and test a webhook. I get an error as a response.

I created 2 webhook and got 2 different errors.

 Namely (see images):

For the first webhook I get the error 301:

https://drive.google.com/open?id=1ZeR4yMPr_zmdA1T1WvbSCN39VjLqMYCV

https://drive.google.com/open?id=1r6hbpfIV6YjicdwdG-d56i0aHfasSe0d  

For the second webhook I get the error 503:

https://drive.google.com/open?id=1ZeR4yMPr_zmdA1T1WvbSCN39VjLqMYCV

https://drive.google.com/open?id=1vL-6l-Q1KZWfHtxawkbTGlmSNECg3yrJ

How can I solve it? Much help appreciated.