Safari will not open on MacBook Air.

2017 MacBook Air

Processor 1.8 GHx Intel Core i5

8 GB memory

macOS Sierra version 10.12.6

When I opened my MacBook Air this morning, I was notified that an error had occurred and it restarted. Upon restarting, among the applications previously in use, the only ones that reopened were Numbers and Microsoft Word. Safari along with the tabs that were previously opened, did not open and when I attempt to click the Safari app icon to open it, it doesn't open and the icon doesn't bounce up and down as the other applications would. How can I access Safari with this problem?