Short Answer
You must notify your employer of your illness before your official shift or workday begins.
Failure to report your absence promptly is a breach of contract that can lead to a formal warning, regardless of how sick you actually are.
What Most Expats Don't Realize
You thought it was acceptable to wait until you woke up at 10:00 am to tell your boss you wouldn't be coming in. You didn't know that German labor law requires "immediate" notification, so your employer issued a formal "Abmahnung" (written warning) for unexcused absence. You lost your eligibility for a year-end bonus and placed your future employment at risk because you didn't send a simple email at 7:30 am.
What To Do
- Email or call your direct supervisor and HR department at least 15 minutes before your workday starts.
- State clearly that you are "arbeitsunfähig" (unable to work) and provide an estimated duration for your absence.
- "Ich melde mich krank und werde voraussichtlich bis Mittwoch fehlen." (I am calling in sick and expect to be out until Wednesday.) — send this text or email to your manager immediately.
The Truth
Germany grants high levels of job security for the sick, but that security is predicated on the "Meldepflicht" (duty to report). The system treats a late notification as a disciplinary issue rather than a medical one.