Some third-party apps have been facing issues with iCloud sync and CloudKit for several months now. The developers of a few of the affected applications claim Apple has now fixed the issue and provided additional details about what caused the problem.

Some developers affected by the iCloud sync issue told 9to5Mac that Apple reached out to them. The tech giant confirmed that the iCloud syncing problems have been fixed. Apple did not delve into the details about the exact cause but said that the underlying issues led to “Service Unavailable (Error 503)” messages for the end-users. The error usually occurs when request-throttling begins for specific users, but in this case, a bug impacted this safeguard, causing an unusually high surge in errors.

Apple is still said to be in the process of communicating the fix to the developers, indicating that the fix is rolling out in a phased manner. To get you up to speed, users of some third-party applications reliant on Apple’s iCloud infrastructure saw “Service Unavailable” errors with “HTTP Status Code 503.” The applications have been plagued by the issue for several months now. The problem is well-documented on Apple’s Developer Forum threads and Twitter.

Tapbots developer Paul Haddad took to Twitter to say explain that the company added a dedicated “Sync Status” dashboard to Tweetbot in the latest version of the app because “iCloud has been so consistently unreliable.”

iCloud has been so consistently unreliable that I decided to add a full settings view just to give users some insight as to what might be broken. pic.twitter.com/uzHCs5M5K3

— Paul Haddad (@tapbot_paul) January 16, 2022

Streaks app’s developer Quentin Zervaas also mentioned the iCloud issue on Twitter.

I’m getting a ton of them. For me they started in May and almost fully resolved about a month ago.

Now back with a vengeance this week. Basic queries like fetching zone list, or a CKQuery with no predicates.

— Quentin Zervaas (@qzervaas) January 22, 2022

As a remedial measure, some developers, such as those behind the calculator app PCalc, resorted to completely disabling iCloud sync via an app update. Others created custom in-app status boards to inform users of the issues with iCloud. The developer of the popular note-taking app GoodNotes penned a dedicated support article to address the issue. Most developers have taken the blame for the issue, although the problem was Apple’s to fix.

Despite the severity and persistence of the problem, the Cupertino giant has not commented publicly on it. Did you face similar iCloud sync issues in third-party apps? Share your experience with us in the comments section.