PREVIOUSLY: Gmail users were met with issues sending and receiving emails on Tuesday morning.
The problem may be affecting Gmail, as well as Gmail via Google Apps.
Down Right Now reported a "likely service disruption" for Gmail after 9 a.m.
Around the same time, the Google Apps Status Dashboard showed a service disruption for Google Mail; other services appeared to be functioning normally.
According to tweets, Google is informing some users that messages cannot be delivered because of a server error. The following message pops up after a failed delivery attempt: "Oops... a server error occurred and your email was not sent. (#758)."
Other users on Twitter say that their accounts are inaccessible this morning because of maintenance.
Have you experienced problems accessing your Gmail account or sending emails? Let us know in the comments.