Try another browser or a private or incognito browser window. If that works better, try clearing your browser cache in the original browser and deleting eBay cookies. Or try using the eBay app.
Try using a different sign in link:
https://signin.ebay.com/ws/eBayISAPI.dll
https://www.ebay.com/signin/?sgn=reg&siteid=0
You seem to be signed in to the community pages; try using the link under the blue gem icon in the upper right corner to reach your My eBay page.
You may be able to avoid a sign in loop by using a social media account to sign in, if you have previously linked such an account to your eBay account.
