Webhooks not sending on submit?

Desired behavior:
on a user submitting the form, the data is collected into json format and POSTed to an endpoint.

Current behavior:
user submits form, data is logged in zoho forms, but I never receive a POST with the data. Please note that this was working properly when I set these forms up in November, last known date of working was February 28th.

Set up:
forms are set up to send webhooks (form> integrations> webhooks) with the enable box checked, the url is in the format " https://domain.tld/endpoint" with the parameters I want and it is saved. users are directed to use the form hosted on zoho.

Observed:
when receiving POSTs from other sources, I am able to see it appear in the server logs. however when testing the form I do not see a log entry indicating a request has been received and no action is taken that would normally occur if a POST had been received.

Steps Taken:
I have checked my configuration to verify that the appropriate ports are open and being listened to. I have tested the endpoint with GET and POST requests from other sources. noting that the ssl certs seem to be properly used.

needed:
are there additional things to check on my end? Is this a problem on zoho's end?