### Steps to reproduce
How can we reproduce the issue
Use Extended Choice parameter with value as "Foo,Bar,Test" (multi-select) and delimiter as ";"
### Expected behaviour
Parameter should pass as simple parameter only as (Foo;Bar;Test)
### Actual behaviour
I am getting the following log message "Job property '%s' is not a Simple parameter. Keeping default value"
### Server configuration
**Operating system**:
Windows
**Jenkins Version**:
Jenkins ver. 2.190.2
**Plugin Version**:
1.026
**Mail Server**:
Microsoft Exchange Server 2016
### Additional Steps/Questions
- [ ] Can you please provide all the configuration details you're using (hide sensitive fields) and any other information which may help? (does it match the [examples here](https://github.com/jenkinsci/poll-mailbox-trigger-plugin#office-365)?)
- [x] Do you know if you're you able to connect to to your mail server via IMAP?
- [x] What log messages do you receive, when you press the "Test Connection" button?
- [x] Have you followed the [troubleshooting section on the plugin page](https://github.com/jenkinsci/poll-mailbox-trigger-plugin#troubleshooting)?
If you're feeling ambitious, you can also try [setting up a LogRecorder for the Jenkins plugin](https://wiki.jenkins-ci.org/display/JENKINS/Logging) (the logger package name will be something like "org.jenkinsci.plugins.pollmailboxtrigger"). This may provide extra insight into why your issue is occurring.