Recently I\'ve been getting a popup when pushing or pulling from upstream
git-credential-osxkeychain wants to use your confidential information stored in \"githu
This appears to have been an issue with MagicPrefs. I quit MagicPrefs and my symptoms have disappeared.
(ref: https://apple.stackexchange.com/questions/208704/os-x-10-11-unable-to-press-allow-on-keychain-access-dialogs )
-- original answer below for posterity -- I found that this occurs with some sort of failure with Keychain Access. The reason I say that is because I also had the problem clicking the button Allow or Always Allow (but not Deny) when changing another aspect of Keychain.
authd.log file shows "Succeeded.." for what appears to be each time I pressed Accept it however the modal dialog box does not disappear.
Solution for me: Restart, did not have to re-enter my credentials like the solutions above. :(