When I hit a POST call from collection, I am getting a 200 response, but I use the same POSTcall in action or flow, getting 0 as a response, and I don’t see any network activity.
Hey @vijaymkm1981 
Thank you for posting the question - Could you provide more details and screenshots to help explain there problem, please?
It’s a bit tricky to know what you have done so far without the contextual information 
I have a series of complete URLs (over 100) that need to be accessed using the POST method. Sensitive information such as client ID and client secret has been masked in the URLs. When I send requests individually—one at a time—I receive a 200 OK response consistently. However, when I attempt to send all requests sequentially in a loop, I receive a 0 response for each, indicating that the requests are not going through as expected.
https://?Number=1234&cpNumber=1234567&jobID=12345678&jobName=Unassigned+test&po=345-45678&employeeID=test&sourceSystem=IPPPLUS&deliveryType=1&deliverySubType=&deliveryNumber=234567890-0&submitUserName=test&deliveryReceiptEmail=test.test%4084test.com&parentOrderId=&containsESeries=0"eGUID=cf1b0e74-1234-4361-7890-123456789012345&customAddress=0&containsHeritage=0&thdFileId=&dealer3222Number=&scheduledDueDate=20211006&deliveryLocation=&skuNumber=&isAutoScheduled=true&constructionType=testing+test
does this request return xml or json?
is it a privately hosted api? (is the api accessible from a vpn only?)
Response is in JSON, and it is not a privately hosted api.
I not sure this will make any difference. Through Actions, All the calls are using User- Agent : “PostmanRuntime/7.44.0” but when hit the URL directly I see the User- Agent : “PostmanRuntime/7.48.0”.