Okay, I looked into this and the issue is related to the Weather Underground API call made from the app. It uses http:// instead of https:// therefore the browser is denying it since the remainder of the site is SSL encrypted.
The fix has been posted to the code: https://github.com/OpenSprinkler/OpenSprinkler-App/commit/20958d726a79c7173d490ae8acea0ef3bfba4d80 and will be released in the next app update (1.4.2) which should be out by the end of the week.
Thank you for the report!