https://paypal.com/cgi-bin/webscr endpoint returning 404 when sending Empty 200 Response

[Gusanito2013]

Not a sandbox issue but I couldn't figure out where else to post this.

I've had my IPN listener in place for over 6 years, nothing has changed but everything has stopped working. 

I've added some diagnostics & the issue is happening where I'm doing step 2 in the IPN flow and sending the empty 200 response to https://paypal.com/cgi-bin/webscr but it returns a 404 & consequently the flow isn't completed & the purchases aren't completing (though paypal is taking the money)

Please can somebody help with this - I'm getting desperate here

[manzwebdesigns]

I have a client who is having the same issue.

[Gusanito2013]

I have now removed that call altogether and it works fine. Involved a bit of rework to the logic though

[manzwebdesigns]

Oh, mine is just a form on a page... see the bottom of https://www.pondvalleylabradors.com/labrador-retriever-puppies/

[davegolfer_22]

I had this problem too. Mine had been working since 2016 then suddenly stopped. My problem was that I added the cmd=_notify-validate to the end of the END of the list of parameters instead of at the beginning. From their IPN guide:

Create a request that contains exactly the same IPN variables and values in the same order,
preceded with cmd=_notify-validate.

I changed my code to add the cmd=_notify-validate to the beginning of the list to fix the problem. I hope this helps.