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For security reasons, instead of using shared credentials and a shared user, it is recommended to create a dedicated user for N.Rich
The Salesforce user must have read and write access to SFDC API including Accounts, Contacts, Opportunities objects as well as any objects used for identifying product-association of opportunities.
You need to add the following N.Rich IP addresses as trusted from SFDC (see https://help.salesforce.com/articleView?id=security_networkaccess.htm&type=5):
178.62.231.47
176.31.229.103
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