If you are running into problems when checking out -- specifically, getting a spinning progress ring immediately after signing in to PayPal -- see this old thread for some possible things to try:
https://community.ebay.com/t5/Technical-Issues/Ebay-Checkout-Issue-not-Connecting-to-Paypal-Undefine...
Many users experiencing that problem in the past have better results when switching to another browser, or temporarily disabling ad blocking and cross-site tracker blocking on eBay and PayPal, or else using a mobile browser or the eBay app to checkout.
Check to see if you have the latest version of your browser or if there is an update available.
https://www.whatismybrowser.com/
Make sure your browser is not blocking cookies or third party cookies. Try temporarily disabling any common add-ons in both browsers.
PayPal has an option for One-Touch autologin that may allow you to bypass the standard sign in process in your browser; that might be worth trying. You can disable it afterwards if you want.
