AOL Mail is suffering from some issues.

Some of AOL Mail's users have been unable to log in to their accounts since yesterday, and they're starting to get upset.

AOL announced on its Mail blog yesterday that it was performing scheduled maintenance that was "taking us a little longer than expected." It said in the post that users would see older messages in their inbox, while others wouldn't be able to log in.

As the day wore on, the issues users were experiencing continued, prompting the Web company to update its blog with another post last night, saying that "some" of its users were still being affected. At that time, it didn't have a fix and asked users to be patient.

"Some of you continue to be affected by today's mail problems," AOL's Mail Team wrote on its blog. "Unfortunately the issue persists, and has taken us longer than expected to resolve. We understand this is a tremendous inconvenience, and we're working hard to correct this as quickly as possible."

So far this morning, some users are still experiencing log-in issues. And many of those folks have taken to Twitter to express their displeasure.

"Anybody know what is going on with AOL Mail" one person asked on the social network. "[I've] been typing the right password, but it's been saying it's not correct."

Another user said that they were finally able to access their e-mail today, but when they got back to their inbox, they found that the last two months of e-mails were "gone."

That sentiment was echoed by a tipster to CNET News who said that "a large group of people are still missing almost two months worth of e-mails, several of them stating that important business documents are gone."

AOL's users have also criticized AOL on the company's help page. As of this writing, 481 answers have been given to a user asking "what's going on" with the company's e-mail platform. The page has been viewed over 150,000 times.

In an e-mailed statement to CNET, an AOL representative said that "less than 1 percent of users are impacted" by the issue right now. The company said that it's currently working with those affected users "to help remedy the situation."

Updated at 12:02 p.m. PT to include AOL statement.