If you are having trouble logging into your Roadrunner email account, double check that your link to the internet is working. An easy way is to refresh the page, or try to find another place. If you have no communication issues, you may then need to go through some simple tests.
Only, make sure you use the correct login tab. The right URL is: https:/www.spectrum.net/login/ and the old mail.twc.com, the Roadrunner email login pages for webmail.runner.com and RR.com do not work. If you've bookmarked one of those pages previously, change your bookmark to use the latest login page instead.
First, you need to check to get your login credentials entered correctly. Some problems can be hard to find, such as using a 'zero' rather than a 'o' so search carefully. If you normally copy and paste your login credentials from a saved document, make sure you did not copy a SPACE unintentionally at the beginning or end of the document.
Your password is case sensitive, so you'll need to be cautious about upper and lowercase letter placement. Make sure you don't capitalize letters that shouldn't be capitalized unintentionally and turn off CAPS LOCK.