Unable to create profiles

A user emailed me saying they were having issues signing up for a membership and that paypal kept emailing them saying it was unsuccessful, so I updated to the latest version of the plugin, I then realised that the ipnhandler wasn’t working, I upgraded my PHP version and that stopped it from error 500-ing, but I still can’t get signups working, I click on the user level, go off to paypal, come back it says everything is fine, then 3-30mins later I get an email from paypal saying it was unsuccessful, I check on paypal and the profile has been created and then cancelled without the initial payment being taken (I assume the inability to take the initial payment is what is causing it to fail). If I hit the ipnhandler url then there is a lot of output, which I’m not sure if that is right as it outputs a lot more than the docs suggest it should. I’ve set define(‘PMPRO_IPN_DEBUG’, true); but didn’t receive an email, I’ll try define(‘PMPRO_IPN_DEBUG’, ‘log’); next, but is there anything else I can do to get to the bottom of it? I am using paypalexpress as the gateway.