Adding subtitles but can not select language

[pingchesu]

Describe the issue
First of all really thanks for the great work!!
I try to upload subtitles for my video content. However I can not select any language in subtitle upload page
Anyone who can help me?

To Reproduce
Steps to reproduce the issue:

1. Go to Edit Subtitle Page
2. Upload subtitles
3. Can not select any language

Expected behavior
Upload subtitle and selected language

Screenshots

There is no language that I can select, hence I can not upload my subtitles

Environment (please complete the following information):

• OS: Ubuntu
• Installation method: Docker install
• Browser: Chrome

Additional context
Add any other context about the problem here.