Exchanges are being released every day and it is important for you to make a careful search on any platform you are about to get into as some aare just their for selfish reasons. The others might not be efficient enough and so many things to consider
The coinopt is a very good example of a platform to avoid, it started some years ago and went offline due to some reasons which where not revealed to the users. They were just around for some short period of time and they look to be like an abandoned project. Their is no trace of the exchange online, it is a good Example of platform to avoid as they aare no longer accessible. Wait for further information From the users