Dropbox throwing SSL errors for some users

[Fahad G.]

Hi

We've got a few users on iOS (iPhone 6 plus, iOS 😎 that have been complaining that Dropbox for them isn't working. Upon inspection, it seems it's failing on all SSL communication with errors such as:

"[ERROR] DropboxSDK: SSL Error. Cannot validate a certificate for the host: api.dropbox.com"
[WARNING] DropboxSDK: error making request to /1/search/sandbox - (-1012) Error Domain=NSURLErrorDomain Code=-1012 "The operation couldn’t be completed. (NSURLErrorDomain error -1012.)"

Or:

CFNetwork SSLHandshake failed (-9806)
CFNetwork SSLHandshake failed (-9802)
CFNetwork SSLHandshake failed (-9824)
NSURLConnection/CFURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9824)
[WARNING] DropboxSDK: error making request to /1/account/info

Any idea what's happening?

[Greg-DB]

[Moved from "Bug & Troubleshooting" to "API Development"]

Thanks for the report. Have you been able to reproduce this issue yourself? The API, on api.dropbox.com, is being served with a valid certificate:

https://www.ssllabs.com/ssltest/analyze.html?d=api.dropbox.com&latest

That being the case, if this isn't happening for all users, it sounds like there may be something device-specific preventing these in particular from verifying the certificate. Do you know if these devices are jailbroken by any chance? Or maybe these users are behind a captive portal or are on some network that blocks Dropbox?

[Fahad G.]

Thanks Greg, after a thorough investigation, it seems this happens usually when the user's Wifi connection is poor. We were able to get around this by retrying a few times before giving up.