I have been following the instructions provided in the official salesforce developer docs here regarding importing mulesoft apis using sfdc external services for use in a flow. I have followed the instructions to the letter, exactly as they are described and ultimately when attempting to hit the api recieve a "301 - Moved Permanently" response.
For some info, not sure what is relevant and what isn't:
The api is running on a Cloudhub worker in a non-prod environment, and we have a DLB and VPC configured
The external service, named credential, and flow are all configured in a dev sandbox environment.
One thing I attempted was to change the URL in the named credential to the actual endpoint for my mule api (https://nonprod-api.myorg.com/example-api-name-dev/api/v1), instead of https://anypoint.mulesoft.com, just to see if anything changes. Interestingly, the error response changes to "PKIX path building error; no valid certificate found for build path". I switched back to https://anypoint.mulesoft.com, but the fact the error changes may suggest my 301 problem lies with the named credential.
Ultimately I am a little confused why following a walkthrough exactly step by step as it is described leads to this error; this almost suggests to me there is some kind of custom browser configuration on my side that I am not aware of causing some kind of redirect. I have attempted to inspect network traffic with console and wireshark to get some indication of whats happening when I debug the flow and get 301, but haven't been able to see anything unusual.
Edit: I have also ensured the api is working properly by testing the endpoint with postman and receiving a successful response. Everything is working properly on the Mulesoft side.