Hi,

Please refer to the following links:

1.  https://www.odoo.com/documentation/18.0/applications/finance/payment_providers/paypal.html

This documentation explains how to configure and test PayPal.

2. https://www.cybrosys.com/blog/paypal-configuration-in-odoo

Hope it helps.

General Steps to Troubleshoot Odoo Server Errors

1. Review Server Logs:
   • Access your Odoo server logs, typically located at /var/log/odoo/odoo-server.log or a similar path depending on your installation.
   • Look for error messages or tracebacks that occur during the transaction process.
2. Check for Custom Modules or Third-Party Add-ons:
   • Identify if any custom modules or third-party add-ons are involved in the transaction process.
   • Temporarily disable these modules to see if the error persists.
3. Validate Transaction Configuration:
   • Ensure that all necessary configurations for transactions are correctly set up, including payment gateways, journals, and fiscal positions.
4. Test in a Development Environment:
   • Replicate the issue in a development or staging environment to avoid affecting live data.
   • Use this environment to isolate and identify the root cause of the error.
5. Update Odoo to the Latest Version:
   • Ensure that your Odoo installation is up to date, as newer versions may contain bug fixes related to transaction processing.