shige there's a possibility those two errors are not related. The first one is likely related to one of the live chat extensions.
The second one could be an extension conflict in either the frontend or backend. You could check the browser network tab to see if the username, email and password keys are correctly passed in the request to the API.
PS: to embed Imgur images on the forum, either use bbcode/markdown with the "get share links" feature of Imgur, or paste the link to the Imgur post without wrapping it in an image tag. I have removed the image tags from your post so that Flarum auto-renders an embed with the links.
