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Sorry to hear you’re facing problems 
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In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 29.0.5): Nextcloud AIO v9.3.0
Operating system and version (eg, Ubuntu 24.04): open media vault 6.9.16-1 (Shaitan)
The issue you are facing:
Hello, I have been running NC AIO as Docker on open media vault for a few months now. This works well for the most part. Yesterday in the course of the morning NC was suddenly no longer accessible. The Apache container was no longer running correctly.
This error message is in the logs:
I am not using a reverse proxy. I use xxxx.duckdns.org as my domain. My router is a Fritzbox. I have already tried to withdraw the port release and assign it again. Unfortunately, this did not help.
Does anyone have any ideas? I would be grateful for any suggestions.
In the medium term, I would also like to put AdGuard back into operation, which I had also successfully used as a docker, unfortunately I did not manage to get NC and AdGuard working at the same time (when AdGuard is running, NC is not accessible), but that is of course a separate topic 
Is this the first time you’ve seen this error? (Y/N): Y
Steps to replicate it:
The output of your Nextcloud log in Admin > Logging:
2024-07-29T15:58:24.126616978Z Error: loading initial config: loading new config: http app module: start: finalizing automatic HTTPS: managing certificates for [my-nc-domain.duckdns.org]: automate: manage [my-nc-domain.duckdns.org]: my-nc-domain.duckdns.org: caching certificate: decoding certificate metadata: unexpected end of JSON input
2024-07-29T15:58:27.240317131Z {"level":"info","ts":1722268707.2395134,"msg":"using config from file","file":"/tmp/Caddyfile"}
2024-07-29T15:58:27.244546513Z {"level":"info","ts":1722268707.244189,"msg":"adapted config to JSON","adapter":"caddyfile"}
2024-07-29T15:58:27.250087313Z {"level":"info","ts":1722268707.2487583,"msg":"failed to sufficiently increase receive buffer size (was: 208 kiB, wanted: 7168 kiB, got: 416 kiB). See https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes for details."}
2024-07-29T15:58:27.250119538Z Error: loading initial config: loading new config: http app module: start: finalizing automatic HTTPS: managing certificates for [my-nc-domain.duckdns.org]: automate: manage [my-nc-domain.duckdns.org]: my-nc-domain.duckdns.org: caching certificate: decoding certificate metadata: unexpected end of JSON input
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
PASTE HERE
The output of your Apache/nginx/system log in /var/log/____:
PASTE HERE
Output errors in nextcloud.log in /var/www/ or as admin user in top right menu, filtering for errors. Use a pastebin service if necessary.
PASTE HERE