"The API User credentials are invalid" error when saving API Credentials for MC Connect
|Knowledge Article Number||000214332|
When attempting to complete the MC Connect Integration, you may occasionally encounter one or both of the following errors while trying to save the API User credentials:
"Connection Error: Salesforce is unable to connect to ExactTarget. Please contact your system administrator to ensure the API user credentials are correct."
"The API user credentials are invalid. Please contact support."
There are multiple solutions to this problem, ranging from very quick to fairly complex. Here's a troubleshooting checklist:
1. Make sure the API User isn't locked out. If so, unlock it and try again.
2. Make sure all of the necessary Marketing Cloud IP addresses are whitelisted in your Salesforce instance, per the installation documentation.
3. If your Marketing Cloud account has Login IP Whitelisting enabled, verify that the IP address that you are using to try and save API User credentials is present in one of the ranges saved in that configuration. See more details on Login IP Whitelisting Here.
4. If none of the above steps work, clear the configuration object. This will require a reconfiguration of some aspects of the integration (but not completely install it from scratch), but will usually take care of the problem.