Problem

When testing Magento integration, channel returns the error: 

SOAP-ERROR: Parsing WSDL: Couldn't load from 'https://www.YourURL.com/index.php/api/v2_soap/index/?wsdl=1' : failed to load external entity "https://www.YourURL.com/index.php/api/v2_soap/index/?wsdl=1"

Solutions

There are 4 possible reasons for this error to appear:

1. Web hosting provider does not support loopback connection which is essential for Magento to operate.
- Contact the provider and ask them to confirm whether or not loopback connection is supported.

2. Magento store cannot connect to itself to load external entity "https://www.YourURL.com/index.php/api/v2_soap/index/?wsdl=1"

- Enable WSDL caching in Magento backend: System > Magento Core API > Enable WSDL Cache set it "Yes".

3. Magento is heavily loaded and has performance issues, thus, the request cannot be processed and a timeout occurs. 

- Try again later.

4. The Root CA Certificate has expired.

- Double-check this with your hosting provider and if the certificate is expired, renew it.

Additionally! Double-check if the error message is returned when you open the URL below. It is the URL we use when requesting or sending the information from/to your site.

https://www.YourURL.com/index.php/api/v2_soap

If it still returns the same error - then most likely the syncs won't work as well. This is how the error would look like:

Please contact your Magento developer to resolve this issue.