There is a red 1 next to yellow exclamation mark, it means that there is at least one error, check
jmeter.log file, it might be the case you will be able to figure out what is the problem from there.
We cannot comment regarding whether your JMeter configuration is correct or not, if you can successfully upload the file using browser or any other API client tool - you can record the event using JMeter's
HTTP(S) Test Script Recorder. Just make sure to copy the file, you're going to upload to "bin" folder of your JMeter installation, this way JMeter will generate proper HTTP Request sampler and
HTTP Header Manager.