Can not chose SSL yes and port 143 when setting up mail account

[Bozo0511]

Infos:

• Used Zammad version: 5.0.x
• Installation method (source, package, ..): any
• Operating system: any
• Database + version: any
• Elasticsearch version: any
• Browser + version: any
• Ticket# 1099993

Expected behavior:

When setting up a mail account in Zammad with SSL/STARTTSL it should be possible to type any port.

Actual behavior:

When you setup a Mail account in Zammad and set SSL/STARTTLS to yes. You can not choose the port 143, it will automatically change to port 993

Steps to reproduce the behavior:

-Login as admin to Zammad

• Go to admin -> channels -> E-mail
• Click on "new" to add a new mail account
• Set SSL/STARTTLS to yes
• change port to 143 and click anywhere outside the box

Yes I'm sure this is a bug and no feature request or a general question.