.........My original reply was much longer but you’ve been spared as my WiFi dropped out and I lost it!
Happens to me often: Press the internet back key at top left of page - takes you back to what you have written. Tap to select all, (of your own post) then tap Copy. Try submitting again. If it asks you to sign in, do so and if it auto-saved it should say proceed and publish your post. If not, you can sign in, reply to thread again and paste what you copied
