Royal Mail customers again had trouble accessing the online postage service yesterday, due to further "technical issues".
The company's SmartStamp service has suffered intermittent outages over three days since 19 March, and it also mentioned problems occurring in February.
A Royal Mail spokesperson confirmed that the service was down for about an hour and a half starting from just before midday yesterday.
The company apologised to customers for the inconvenience and said: "The Royal Mail online postage application was unavailable to our customers for a short period yesterday due to technical issues with our website, however the service was quickly restored."
The Capgemini-managed Royal Mail website does not appear to have fully recovered since experiencing a severe disruption to services before Christmas, following a migration of online data to new servers.