If you're actually getting SGS error messages, then the problem is usually with your account and/or Linkpoint/FirstData, and often NOT the hosting company.
Some possible causes:
a) Maybe your bank has changed something? ref: http://www.zen-cart.com/forum/showthread.php?p=437901#post437901
b) From the Linkpoint/FirstData technical documentation:
SGS-020006: Please contact merchant services.
Verify first that the the correct store number is entered. This error normally occurs when contact information is updated with your merchant bank. For example if the business phone number or address was recently updated. You will need to contact LinkPoint/Yourpay support and they will need to generate a new PEM file for your account. You will then need to download the new file and either upload it to your web site or copy/paste it into your shopping cart.
Maybe you need to throw away the old PEM file, ask for a new one, and download that new one, and upload that new one to your website.
c) reference for obtaining/uploading PEM files: https://www.zen-cart.com/tutorials/index.php?article=298
If the logs are showing error #7 - could not connect to host, then the problem IS with your hosting company.
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