[JENKINS-50160] Can't add credentials through https

When I try to add credentials for example login/password for docker registry, nothing happens and I get following error in console (domain name changed to example.com):

 Mixed Content: The page at 'https://example.com/job/dfo-pm-staging_backend_develop/configure' was loaded over HTTPS, but requested an insecure form action 'http://example.com/descriptor/com.cloudbees.plugins.credentials.Cred...ials.SystemCredentialsProvider$ProviderImpl/context/jenkins/addCredentials'. This request has been blocked; the content must be served over HTTPS.

I can change form url to https instead of http using developer tools and then it submits correctly. How do I fix this issue?

---
Originally reported by refruity, imported from: Can't add credentials through https

• status: Open
  
• priority: Major
  
• component(s): credentials-plugin
  
• resolution: Unresolved
  
• votes: 0
  
• watchers: 4
  
• imported: 2025-12-08
  

Raw content of original issue

When I try to add credentials for example login/password for docker registry, nothing happens and I get following error in console (domain name changed to example.com):

 Mixed Content: The page at 'https://example.com/job/dfo-pm-staging_backend_develop/configure' was loaded over HTTPS, but requested an insecure form action 'http://example.com/descriptor/com.cloudbees.plugins.credentials.Cred...ials.SystemCredentialsProvider$ProviderImpl/context/jenkins/addCredentials'. This request has been blocked; the content must be served over HTTPS.

I can change form url to https instead of http using developer tools and then it submits correctly. How do I fix this issue?

environment

```
Jenkins version 2.89.3

Credentials Plugin version 2.1.16
```