Hello,

when I click on "details" of an entry in i2psnark I see nother webpage with details
and a start or stop button (depends if the torrent is started or not).
When I click this button I got an 405:
HTTP ERROR 405

Problem accessing /i2psnark/myfile. Reason:

Method Not Allowed

Powered by Jetty:// 9.3.30.v20211001

How can I fix this?

Start stop from the main page, the overview of all files works when I click the small buttons there.

It could be a lot of things. The best thing is to have a Stanalone i2psnark as an extra. I prefer the i2pplus edition. For internal use for browser try Ungoogle-Chromium (chromium --incognito --proxy-server="http:127.0.0.1:4444"). If you use it externaly you need to be an expert with forbidden extensions from browserleaks.com (read comments). There is a learning curve for i2p and the current issues are junk. You can try the Nix (as an Nix OS overlay) to see if you experience the same error.

Bla...bla...bla
I don't want to ask you for logs http://127.0.0.1:7657/logs or https://127.0.0.1:7667/logs because it is very intrusive and I really don't want to commit to helping you to much. When you ask for help you need to give enough info like:
Ungoogled-Chromium
I2P version: 2.4.0-0
API version: 0.9.61
Java version: N/A 21 (OpenJDK Runtime Environment 21+35-nixos)
Wrapper version: none
Server version: 9.3.30.v20211001
Servlet version: Jasper JSP 2.3 Engine (3.1)
JSTL version: standard-taglib 1.2.0
Platform: Linux amd64 6.6.2-1.qubes.fc32.x86_64
Processor: Skylake Core i3/i5/i7 (coreibwl)
JBigI status: Native BigInteger library libjbigi-linux-coreibwl_64.so loaded from resource
GMP version: 6.3.0
JBigI version: 4
JCpuId version: 3
Encoding: UTF-8
Charset: UTF-8
Service: false
Built: 1970-01-25 11:32:13 UTC
Built By: unknown

This is a hackers delight. No1 helped with fixing some errors and NixOS was hacked and now there are somewhere in the 4 digits routers that stabilize the network. The paid designers who are laughing all the way to the bank are tools/curva that use the same bucket to sh!t and bring their drinking water.