This error is thrown because there is a limit of 5 open HTTP connections per session in the Oracle database server.

Usually, the application intends to open one connection at a time. However, this error might occur due to the application not closing the connection properly after being finished.

So, it’s recommended to review your code and to make sure you are ending the response after you have finished as well as in the exception part also, ending the request like the below code.

Catch too many requests exception to handle it by closing the request and response:

EXCEPTION
WHEN UTL_HTTP.TOO_MANY_REQUESTS THEN
UTL_HTTP.END_REQUEST(req);
UTL_HTTP.END_RESPONSE(resp);

Ending the request at the end of your program

UTL_HTTP.END_REQUEST(req);