Plusnet's servers are spluttering again, with many of the BT-owned ISP's subscribers unable to access their email since yesterday morning.
The whole system had to be taken down for about an hour on Monday after "a couple of hundred" mail accounts with particularly large inboxes were putting too much strain on it.
Plusnet product development director Neil Armstrong said all the undelivered mail was safe and it was working to distribute it as soon as possible by adding extra mail collection server capacity.
The overload could have been caused by repeated spam attacks. "We saw some of these few very large accounts growing very quickly, though there may be a combination of factors," said Armstrong. He added that the problems would be fixed within 24 hours.
Following the universal downtime, service has been patchy, with intermittent outages affecting smaller groups of subscribers throughout Monday and continuing into today.
The Sheffield-based outfit is in the process of migrating email to a new £250,000 server platform, but said its current issues were unrelated to the work, which should be completed within two weeks.
Plusnet's support page for the fault is here. ®