What version of PHP are you using? I would be inclined to clone your site and upgrade the clone to 126.96.36.199 and see if the error still persists.
Also. Try this answer from Stackoverflow:
"Try this in Admin panel:
Go to System > Users > API.
Add a new API, generate password, and enable it, add your IP address in IP tab.
Then go to Admin > System > Settings > Edit, tab Option.
Select API user under Checkout section as your API user.
Save the changes.
Go to Sales > Orders to check if error is gone."
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