Paypal Set-up Issues

[fourthwall]

I had Paypal functioning on my site, but overnight something went goofy and now the Payments page blanks out if the Paypal Payments Standard module is activated. It doesn't matter whether I'm in live or sandbox/test mode, and I haven't installed anything new or changed any settings since it was last working.

Server OS Linux 4.19.150-76.ELK.el7.x86_64
Database MySQL 5.7.23-23
Installed Version: CE Phoenix v1.0.8.3

I'm at a loss for where to even begin troubleshooting this. Any help is greatly appreciated, thank you!

[ecartz]

now the Payments page blanks out if the Paypal Payments Standard module is activated.

I'm at a loss for where to even begin troubleshooting this. Any help is greatly appreciated, thank you!

In general, a blank page creates log entries. I'd suggest starting with those log entries.

[fourthwall]

Thank you for the quick response! Here is the log file.

[20-May-2021 05:58:04 America/New_York] PHP Warning: A non-numeric value encountered in /home3/XXXXXX/public_html/includes/modules/shipping/zipusps.php on line 502
[20-May-2021 05:58:09 America/New_York] PHP Warning: A non-numeric value encountered in /home3/XXXXXX/public_html/includes/modules/shipping/zipusps.php on line 502
[20-May-2021 05:58:31 America/New_York] PHP Warning: A non-numeric value encountered in /home3/XXXXXX/public_html/includes/modules/shipping/zipusps.php on line 502
[20-May-2021 05:58:35 America/New_York] PHP Warning: A non-numeric value encountered in /home3/XXXXXX/public_html/includes/modules/shipping/zipusps.php on line 502
[20-May-2021 05:58:36 America/New_York] PHP Fatal error: Uncaught Error: Call to undefined function tep_session_is_registered() in /home3/XXXXXX/public_html/includes/modules/payment/paypal_standard.php:125
Stack trace:
#0 /home3/XXXXXX/public_html/includes/system/versioned/1.0.7.3/payment.php(140): paypal_standard->selection()
#1 /home3/XXXXXX/public_html/templates/default/includes/pages/checkout_payment.php(34): payment->selection()
#2 /home3/XXXXXX/public_html/checkout_payment.php(25): require('/home3/XXXXXX...')
#3 {main}
thrown in /home3/XXXXXX/public_html/includes/modules/payment/paypal_standard.php on line 125


Any ideas?

[fourthwall]

Scratch that, I redownloaded the module file and got past that part again, but now when I do my test sandbox, payment will go through, but the redirect gives me an error that 'page is not secure' and takes me back to the login page on my site, rather than finalizing the check-out.

The order goes through on the back end, but doesn't appear to have gone through for the 'customer.'