Several things can be going wrong:
Your browser may be caching a failed access attempt.
Try deleting the cache, sometime called temporary internet files, stored by your browser.
Certain content or features might not be part of the library's subscription.
In these cases you won't be able to access content because the library has not purchased access to it. You may get an error message as you try to enter certain parts of a database, or you may see links that appear to be inactive.
You need to use a specific browser to be able to view the database.
Some databases require the use of a particular browser or version of a browser. If you are using an older browser, consider updating to a newer version.