API Endpoint (at Bubble) responses 502 Bad Gateway

Hi!

I have configured an endpoint on Bubble.is which correctly reads out all parameters which are posted by another service. However, the other services always notify me about getting a bad gateway error from my endpoint. This is the response from my endpoint on bubble:

Content-Type text/html
X-Cache MISS from ip-172-18-20-243.ec2.internal
X-Cache-Lookup MISS from ip-172-18-20-243.ec2.internal:3128
Transfer-Encoding chunked

<html><head><title>502 Bad Gateway</title></head><body><h1.>Bad Gateway</h1>An upstream server returned an invalid response.</body></html>

When my endpoint returns a plain text file with any information, no error is caused. However, this text is used by the other services to trigger another event and sends a SMS which is not the wanted behavior.

Do I have to return something that the bubble servers doesn’t send the error to the other service? When yes, what do I have to return (parameters and values).