429 keep getting this

with my original profile on Firefox which always worked before when i got to Mozilla and or Firefox support i get to the page to ask a question it works until i hit submit then i get 429. So i decided to make anew profile with different password and i did the same thing thee and still got 429. Yet i was able go to chrome and ask my question and it worked there. On the Firefox browser current version I had refreshed it in more trouble shooting and removed and turned off add ons and i still get 429. I have contacted Comcast about this and they say my connect is correct. I have tried changing the pass word on my original profile what is the problem with this why does it work on Chrome but not on Firefox itself / What can be done what do i need to do and are you aware . Am i the only on with this problem? How do we fix it