Less than two weeks after tackling a serious set of system problems, Salesforce.com suffered a significant service outage on Tuesday.

The CRM (customer relationship management) services, which have gained popularity because of their cloud procurement model, are divided into many instances around the world, each serving customers in different geographic regions.

Seven instances went down at some time or another on Tuesday, principally in North America.

Salesforce.com's Application Store also went down because it shares infrastructure with one of the downed sites.

According to a notice posted at 12:49 a.m. PDT on Salesforce.com's system status web page said the outages started with instances NA1, NA5 and NA6 in North America.

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Shortly thereafter, the CS0, CS1, CS3 and CS12 regions, which are part of a set of "sandbox" instances Salesforce.com customers can use for development, testing and new feature previewing, were also affected, according to the site.

It wasn't immediately clear what caused the problems. At 2:46 a.m. PDT, Salesforce.com said that power problems had been detected and fixed, but the outages persisted.

A number of instances had yet to be restored by 6:30 a.m. PDT. Search infrastructure for the NA1, NA5 and NA6 instances was experiencing performance issues, according to an update at that time.

Some Salesforce.com customers may still be reeling from the last system outage, which occurred in late June. Those problems were caused by a fault in Salesforce.com's storage tier.