When the Outlook wont open, follow the given solutions:
Restart your computer; sometimes, simple reboots can resolve software glitches.
Try launching Outlook in Safe Mode; this can bypass potential add-in conflicts.
Ensure your Outlook software is updated.
Repair your Outlook program via the Control Panel or Settings.
Scan your PST files for errors and repair if necessary.
As a last resort, consider reinstalling Outlook.