I'm having problems with Jenkins when trying to access a self-hosted Bitbucket-Repository with self-signed certificates:

   Started by user unknown or anonymous
[Fri May 28 13:38:25 UTC 2021] Starting branch indexing...
 > git rev-parse --is-inside-work-tree # timeout=10
Setting origin to https://<companyurl>/testjenkinssslproject.git
 > git config remote.origin.url https://<companyurl>/testjenkinssslproject.git # timeout=10
Fetching & pruning origin...
Listing remote references...
 > git config --get remote.origin.url # timeout=10
 > git --version # timeout=10
 > git --version # 'git version 2.11.0'
using GIT_ASKPASS to set credentials 
 > git ls-remote -h -- https://<companyurl>/testjenkinssslproject.git # timeout=10
ERROR: [Fri May 28 13:38:25 UTC 2021] Could not fetch branches from source 13b4c498-1311-4123-932f-7af6df217cc2
hudson.plugins.git.GitException: Command "git ls-remote -h -- https://<companyurl>/testjenkinssslproject.git" returned status code 128:
stdout: 
stderr: fatal: unable to access 'https://<companyurl>/testjenkinssslproject.git/': server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

What I already tried:

• Adding Certificate to Jenkins KeyStore in Helm Chart

values.yaml:     
master:
  httpsKeyStore:
    jenkinsHttpsJksSecretName: ''
    enable: true
    httpPort: 8081
    path: "/var/jenkins_keystore"
    fileName: "keystore.jks"
    password: "changeit"
    # Convert keystore.jks files content to base64 ( cat keystore.jks | base64 ) and put the output here
    jenkinsKeyStoreBase64Encoded: |
base64valueofmykeystorewithselfsignedcerts

• Add crt directly into the Jenkins Docker Images (like https://github.com/jenkinsci/docker/issues/901), but I'm just getting the same error as in this github issue: "rm: cannot remove 'ca-certificates.crt': Permission denied"
• Use Kubernetes JVM_OPTS Annotation to use my custom Jenkins-KeyStore (solved 50% of the errors, but not the errors thrown when "git clone" is called)

Does anybody have experiences how to add self-signed-certificates to jenkins & the jenkins agents?