Xneelo has informed users that it is experiencing a large-scale spam outbreak that is resulting in e-mail being delayed.
Many Xneelo subscribers have been experiencing delays when sending emails to external recipients.
Some users have also received messages that the IP address they are attempting to send the email from is on the Spamhaus blacklist.
“You will receive the following error when attempting to send an email: 550 Spamhaus (-53): retry time not reached for any host,” Xneelo said.
The company said its engineers have rolled out a change that should resolve the error being encountered.