Update: I just noticed that this is a known bug.
Local Calendar can’t edit or delete · Issue #112561 · home-assistant/core (github.com)
I’ve a problem with calendar integration.
I added an entry manually and then want to change it. Deleting it no longer works either.
I get the following error message:
Unable to parse date/time value: [ValueError(“Expected value to match DATE pattern: ‘’”), ValueError('Expected value to match DATE-TIME pattern: ')]
Does anyone here have an idea?