Email and payment not working

Hello,

I have installed WP-invoice plugin on my website using stripe in test mode.

When i create an invoice or send notification of invoice, the email is not sending.

Also the payment of invoice is not receiving.

Here is the URL with invoice form:
https://www.sigmamobiles.com/invoice/?invoice_id=27c3a2ac85a8b777dd56bdfaa292efdd

https://www.ads-software.com/plugins/wp-invoice/