Generally, closing the Application completely
Then, hold the SHIFT key and try to launch the application from the Applications folder
This is called a Safe Lauch of only the application
Does this work ?
If not >>
Restart in Safe Mode.
This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts.
The boot up will be slow and can take some time – Normal.
Safe Mode will also eliminate Third Party Software, extensions and drivers from loading.
It will only load the Minimum amount of Core Apple Processes to allow the the computer to function at a reduced Level of Performance
Does the issue present in this mode ?
Sometimes a Safe Boot followed by a Normal Boot will just put things right.