Officials said in a statement Tuesday that the problem had been fixed and that it hoped to release the vote tally on Tuesday.
The Iowa Democratic Party said Tuesday that its new app, meant to speed up the reporting of caucus results, suffered from a "coding issue" that instead led to a significant delay in counting and reporting results.
The error, which caused accurately collected data to only be partially reported, pushed the party to resort to manual backups.
"As part of our investigation, we determined with certainty that the underlying data collected via the app was sound," Iowa Democratic Party chairman Troy Price said in a statement. "While the app was recording data accurately, it was reporting out only partial data. We have determined that this was due to a coding issue in the reporting system. This issue was identified and fixed."
Price also said that the party has been able to verify the vote counts through "required paper documentation," but did not promise that results would be reported on Tuesday.
"Precinct level results are still being reported to the IDP," he said. "While our plan is to release results as soon as possible today, our ultimate goal is to ensure that the integrity and accuracy of the process continues to be upheld."
Price said there was no indication of any outside effort to affect the app or the reporting of results.
"We have every indication that our systems were secure and there was not a cyber security intrusion," Price said. "In preparation for the caucuses, our systems were tested by independent cybersecurity consultants."
Early in the day, Democratic county chairmen in Iowa said that some of their precinct leaders had trouble downloading and installing the app, and others received error messages. Two of those chairs said they were going to use manual methods and call the results in on a hotline.
But caucus managers reported extended wait times on the hotline, leading to frustration and confusion.
This story is developing. Please check back for updates.