The application "Google Chrome" is not open anymore I can not open external hyper link using Chrome as my default browser.

Example: if I click a link from Mac Mail nothing happens. If I click a link from tweetdeck I get this error: The application "Google Chrome" is not open anymore.

When i switch my default browser to Firefox then web pages are opened as expected in ff.

OSX V. 10.11.6

Chrome V.  54.0.2840.98 (64-bit)
Sometimes uninstalling and reinstalling applications helps to solve problem.  Try that and see if it works.