I noticed since yesterday that i couldn't access some links on my yahoo account like draft sent etc and today mails couldn't be sent.
Just heard them announce now that users will be experiencing itches....
So keep fingers crossed and don't panic engineers are on it

Source....

UPDATE Wednesday, 12:31 p.m. MT:

Yahoo Mail used its social media accounts on Wednesday to updated its users on the email outage.

"We are very sorry for recent difficulties with Yahoo Mail.

Some of our users have not been able to access their mail since 10:27 PM PT on Monday night, due to a hardware problem in one of our mail data centers. The issue has been harder to fix than we originally expected.

We have dozens of people working around the clock to bring it to a resolution. We believe our current efforts will restore our users' access to their inboxes by 3 pm PT today. We'll post again then on our @YahooMail Twitter handle.

by Jeffrey Bonforte, SVP of Communication Products"

Yahoo Mail has been using its social accounts to let its users know what is happening.

Yahoo Mail posted this on its Facebook page Tuesday afternoon: "We're aware some users are unable to access Yahoo Mail and apologize for any inconvenience. You can continue accessing your Mail via tablet or Smartphone, and we are working now to try and restore all access in the next few hours."

This post has several responses from Yahoo Mail users that they cannot open their mail using a tablet or Smartphone. To these comments, Yahoo has responded that they are still working on the issue.

Last week Yahoo announced it would no longer allow people to access their mail unless they use a secure access point.

"We've recently updated our servers for your safety and now require a secure connection when accessing Yahoo Mail from a mobile device or mail client," Yahoo Mail published in it's help center.

Yahoo Mail users need to check their device settings to make sure SSL is turned on. If users are logging on through a web browser, https needs to be used in the web address.

This comes as Yahoo and other organizations like Gmail and Facebook have been hacked and user passwords compromised.

Yahoo Mail posted this on Facebook Tuesday morning:

"As we posted last week, Yahoo takes security very seriously and is working to protect your inbox. We're shutting down non-SSL access to Yahoo Mail via POP and SMTP starting today.

To prepare for this change, or if you're having network connection issues, we encourage you to check your device's settings and enable SSL connections so you can continue to access Yahoo Mail: http://help.yahoo.com/kb/index?locale=en_US&page=content&id=SLN22197