@sdetweil Thanks for your reply.
It’s a bit crazy. I completely reinstalled everything two days ago using copy and paste from the module page.
Then I copied the .env file from the old installation to the new installation.
Could this be because I copied the .env file from a backup into the directory after the reinstallation?
Thanks for the feedback, because I’d like to learn from my mistakes.

@MMRIZE

Hello,
Please Can you help me and Sorry for my bad English.

I have a Problem wit the CalDAV Module in Magic Mirror2.

in the pm2 error Log File i have this Message:
[2025-09-04 11:42:08.001] [ERROR] Error when loading MMM-CalDAV: Cannot find module ‘dotenv’
Require stack:

• /home/magicmirror/MagicMirror/modules/MMM-CalDAV/node_helper.js
• /home/magicmirror/MagicMirror/js/app.js
• /home/magicmirror/MagicMirror/js/electron.js
  [2025-09-04 11:42:08.379] [WARN] You’re using a full whitelist configuration to allow for all IPs
  [2025-09-04 11:42:17.749] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/FAMILY_Familienkalender.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
  [2025-09-04 11:42:18.028] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/NINA_Arbeit.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
  [2025-09-04 11:42:18.226] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/DOMINIQUE_Klasse7d.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
  [2025-09-04 11:42:18.406] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/SAMUEL_Klasse4f.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
  [2025-09-04 11:47:17.764] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/FAMILY_Familienkalender.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
  [2025-09-04 11:47:18.035] [ERROR] Calendar Error. Could not fetch calendar: http://localhost:8080/CALDAV/NINA_Arbeit.ics Error: Not Found
  at NodeHelper.checkFetchStatus (/home/magicmirror/MagicMirror/js/node_helper.js:102:9)
  at process.processTicksAndRejections (node:internal/process/task_queues:105:5)

The following errors are clear thats the result from the First ERROR.

What im doing Wrong or thinking false?