re 1) : sorry, popup (or not) is a global settings

re 2) : you cant (not by using the options available in the plugin anyway) as that’s a fundamental part of how wppizza works
(but you could probably do some custom jquery $element-id.trigger(‘click’) in some circumstances)

please also re-save your wordpress permalinks once (WP->Settings->permalinks)
wp-admin/options-permalink.php

and lastly – for now – make sure you enable debug as described earlier and check the debug log when making an order with paypal. if some plugin (wppizza related or not) for one reason or another throws a fatal error for instance, then that needs to be fixed

have you checked the server access logs ?
is there any access there to /ipn/ipn.php (other than the direct access I or you might have tried when diagnosing what the issue is) ?
if not , then paypal gets blocked server end. perhaps mod_sec installed without telling you ? some firewall rule added ?
if this all worked for over a year as you say , then the last 2 sound like good contenders….
(though typically, if that is the case paypal will not say “sent” but “retrying” or “failed” or similar)

also, given that it worked for over a year , is there anything that was changed between it working / not working (plugin updates – mainly some wppizza stuff but perhaps some other things might also cause issues, or server software and the like ) ?

i also noticed that you have a rogue " /> on your site at line 4 which can cause all sorts of issues (not necessarily regarding paypal, but you might want to fix that regardless)

for wppizza v3, the gateway logging has been made global and moved to
/wp-admin/edit.php?post_type=wppizza&page=settings
to log all these files in the same place, wppizza/logs

so first question is:
are there any paypal related logs in that directory (wp-content/plugins/wppizza/logs/)?
did you receive any notices/emails to your admin email regarding paypal errors of some sort ?

that said, if you dont receive any IPN notifications in the first place , there’s nothing to log as it never reaches the server.
can you show a screenshot of the ipn order history of your paypal account ?
do those notifications say “sent” or do they say something else ?

and how is that a “vague place” anyway? it is specifically written for the wppizza paypal plugin

what are you talking about ?
do you want me to copy and paste what it says in the troubleshooting section ?
i cannot possibly do any of this for you as i have no access to your server nor to your paypal account
once you give me some sort of information as asked there , i might be able to help further

secondly, you have not even provided the most basic info like a link to your site
do you want me to guess what version(s) you are running or plugins you are using ?

furthermore, from what i can see i replied to absolutely all emails (not only yesterday , but going back months and years)
checked your spam folder ? what email did you send it to ? what’s the subject line so i can search for it , in the unlikely case i overlooked this

i cannot see any topics that are in the moderation queue either