The deadline for retailers, brands and other organizations to apply for new top-level domain names—essentially, new web addresses that could better reflect a company’s activities—was extended today because of unspecified technical problems.

The Internet Corporation for Assigned Names and Numbers, or ICANN, had planned to end the first round of applications for those domain names today. But the group will keep accepting applications until April 20. That’s because of a “technical issue” involving the software used for the application process. ICANN gave no further details of the problem, but said the application system will be shut down until Tuesday.

A top-level domain is the term that follows the final period in a web address, such as .com, .org and .gov; 22 such domains exist, along with about 250 country-specific domains. ICANN is working to expand available domains by enabling retailers and other entities to create or buy domains that describe their work. For instance, a camera company could use the .camera domain, or a subdomain that includes .camera. A retailer could create its own domain, such as .Macys and create web addresses such as dresses.Macys and furniture.Macys. Few organizations have confirmed they have applied for domains, but Google earlier this month said it  is applying for domains related to its name.

The extension gives a bit of breathing room to potential domain applicants, says Bruce Tonkin, chief strategy officer of Melbourne IT, an Australia-based firm that sells domain name services. “Applicants have a little more time to ensure their final payments reach ICANN, and to secure financial instruments such as letters of credit before the system closes,” he says.

ICANN has approved at least 290 registrants for the top-level domain names. A registrant can apply for up to 50 new top-level domains. Each registrant has submitted a $5,000 deposit but not necessarily an application for new domains; registrants are really filing expressions of interest. ICANN plans to reveal the domains for which registrants have applied May 1, and for the new domains to begin operation in January 2013.

Many trademark and ICANN experts predict a second round of domain applications after that; those experts anticipate that many potential applicants will hold off until they see how the first round goes. ICANN officials haven’t ruled out a second round, and it remains unclear when a second round would start.