The spinning wheel or flashing screen could be caused by various factors. First, try clearing your browser cache and cookies. Ensure Opera is up-to-date, disable extensions, and use a private window to troubleshoot. If the issue persists, consider reaching out to PayPal or Opera support for specific assistance.
I can't guarantee that those steps will definitely solve the problem, but they are common troubleshooting measures that often help in resolving browser-related issues. If the issue persists, reaching out to PayPal or Opera support may be the best course of action, as they can provide more tailored assistance.