Just to mention, I don't know the full extent of how you are using <a href="https://i.imgur.com/AgPTTw9.png" rel="nofollow">https://i.imgur.com/AgPTTw9.png</a> , but Mods can't use any images for token/avatars which are not in a user library. Something on imgur could be output to chat, or possibly embedded in the text of a handout, character sheet bio, or roll template output, but will cause errors like the one above if needed in other contexts. If you wanted to use that image as a graphic on the table top, you'd need to upload it to your user library, then get the URL from it (probably by selecting it, hitting Z, and right click-copy image url).