UPDATE: Xero told the Herald shortly after 10am: "We have identified the underlying issue that has been causing disruption to customers accessing Xero. This was related to a platform certificate issue at approximately 3am NZT which we have now resolved. We have implemented a fix and our service is recovering." Experts said it was possible new internet rules about renewing SSL security certificates on a more frequent basis caught out both Xero and Slack. (SSL or secure sockets layer protects the data of people who visit a site.) On that point, a Xero spokeswoman responded: "This issue was caused when a certificate our systems required expired and some of our subsystems did not automatically trust the new certificate. It is not related to any third-party provider."
Xero is suffering a major outage, which seems to be affecting many of its two million subscribers around the world.
The Wellington-based cloud accounting firm has drawn complaints from New Zealand firms trying to process end-of-month billing, but its social media feeds also feature complaints from users in the UK, US and elsewhere.
Xero's status page first reported an issue at 3.24am NZT, saying: "Users are experiencing errors and slowness while using Xero. We are currently investigating this issue."
Nine further updates have offered apologies ("We acknowledge the disruption and inconvenience this issue is causing during a critical time of month") but no explanation of what is causing the issues, or an estimated time for them to be resolved.
The latest, at 6.13am NZT, says: " Our Product Team is focused on resolving this issue. This continues to be our top priority, and we apologise for the disruption."
"Come on @Xero. What were you doing the whole night, sleeping? When you have thousands of customers with their finances on your hands. Wake up @Xero and fix this issue ASAP!!!," Tauranga entrepreneur Natan Leon posted.
A social media manager for Xero replied: "We have a team of experts on this and were on it the minute it happened. I'm sorry it's taking time to fix and can only thank you for your patience."
And a Plymouth, England-based small businessman posted: "Sorry to anyone expecting to get paid this month, can't access bills because @Xero won't let me!"
UK accountant and tax adviser Kris Milovsorov tweeted: "Last week, @Xero significantly increase their subscription costs.
"This week, a major outage.
"Perhaps take some of that cash and invest it in back-up systems? "
And London man Andrew Rippington posted: "What's going on @xero. We're looking into it isn't good enough."
A spokeswoman for Xero could only offer the boilerplate: "Xero is currently experiencing an issue preventing users from being able to use and navigate the platform. Our technical teams are urgently investigating the matter."
Slack stuffs up
Meanwhile, popular workplace collaboration software Slack - recently bought by Salesforce for US$27.7b - has been unavailable for some users this morning.
In this case, Slack has admitted the cause was self-inflicted, as a change it made to its domain name servers (which manage access to its services at Slack.com) went haywire - and it's now waiting on internet service providers to clean up after it.
Slack's latest update indicates the level 4 lifesaver could be offline for quite some time, for some users.
"We are aware of connectivity issues related to DNS [domain name server] that are impacting a small subset of users," Slack said in its latest status update.
"This issue was caused by our own change and not related to any third-party DNS software and services. In order to resolve this faster, your ISP (Internet Service Provider) will need to flush their DNS record for slack.com.
"We expect all customers' connectivity issues to be resolved within the next 24 hours. We know how important it is."