Even Outlook pros run into issues. Here are some frequent problems and solutions:

ProblemSolution
Outlook won’t openRestart PC, run Repair Office via Control Panel
Emails stuck in OutboxCheck internet, reduce attachment size, restart Outlook
Missing Calendar eventsCheck Sync Settings and account connection
Search not workingRebuild the Outlook index (File → Options → Search → Indexing Options)

Tip: Regularly update Office to avoid bugs and security issues.