I have uploaded a build... I have external testers ready to go... my test build has a yellow light and says "Ready to Submit" but the only button available says "Expire Build."
I have searched everywhere... where is the Submit for Beta Review button? Is it a button that won't appear until I do something else? All my data is filled out.
I had the same situation. I ended up discovering to submit it this way: In iTunes Connect, select your app. Then go to Testflight > External Testers > Builds > Click + Build > Select Build > Next > Next > Send for Review.
The reason for this (at least in my case) was that I insisted on uploading the build using the “TestFlight (internal only)” button instead of uploading it through App Store Connect. While the “TestFlight (internal only)” button allows you to test the build internally, the App Store Connect option enables you to upload the build to an external testing group on TestFlight and also submit it as an update for regular users on the App Store.