These may take some time getting correct as a single mistake invalidates the captcha, and thus taking so long, may expire the support submission sent prior. At least for me, this appears when completing the captcha. I’ve tried both the mathematical captcha and the audio captcha.
In 2019, I encountered the same bug. I resolved it by clearing my browser and waiting a few days, and it eventually fixed itself.
If you’re using Google Chrome and don’t want to disable any extensions, try enabling multiple profiles. Use the guest profile, which has no extensions or customizations, to handle this one support ticket.
Alternatively, you could wait a few days and then try this approach.