Assuming you have not bookmarked the wrong page, you may be encountering a malicious redirect.
Try scanning your computer for adware or malware. If that does not turn up anything suspicious, try clearing your browser history and cookies. If you do not have an ad blocker, try installing one. Or try another browser -- in some cases, such redirects target particularly vulnerable browsers, and are often triggered when visiting particular sites like yahoo.com or ebay.com.
Here is an old thread about similar malicious redirects:
https://community.ebay.com/t5/Technical-Issues/EBay-site-redirect-to-virus-scam/td-p/28292480
