Here's why the "invalid source address" fault string appears when using the SOAP API and how to resolve it.
1. First, check out the IP addresses to be allowlisted by navigating to the following screen within the Marketing Cloud:
Setup | Settings | Security | Login IP Allowlist
2. Note the IP address(es) listed in the workspace.
3. Next, view the IP address that's being denied by clicking the "View Access Log" button above the workspace.
4. Create a new trusted IP range for the IP address being denied. As part of the process, you'll need to set the "Login Source" to "Any" or "API Calls."
000387099

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.