Members Unable to Register?

I recently started a Forumotion site to showcase my Chromaicora project (https://chromaicora.forumotion.com), which is a popular webseries set in my personal worlds of fantasy that has begun to spin-off into other forms of media. Since this is a web forum, there are also sections intended to be used by members to discuss things related to the project as well.

Anyway, someone who is both a huge fan of my series and one of my long-distance pals recently sent me a tweet saying that they tried to register on my forum (I'd invited them to be a staff member), but they couldn't due to their chosen username already existing on the server. The problem is that I am currently the only member, so their username shouldn't exist yet.

I've looked into this and tried a solution I found in this very forum (Admin panel > Users & Groups > Inactive Users), but it doesn't appear there, either. This problem may be true for everyone who has attempted to register thus far, so I'd appreciate any assistance on this problem. Please help. Thanks for taking the time to read this, and have an awesome day!

--Zack--

hello and welcome 

Go to admin panel-->General-->Security-->'Dis allow subscriptions of the most commonly used usernames?' tick this to 'No' and save.

I tried it, but they're still having the same problem.

Thank you for the welcome.

tell your member to register with a diffrent name as a test and then go to the admin panel and change it with the name he wants

i registered to your forum just fine

edit: tell your member to clear the broswer cache and history and retry

as you are the founder of the forum you could try the following.

ACP >> General Tab >>  Forum >> Configuration >>

Scroll right to the bottom of the page and look for
Resynchronize your forum statistics :
tick this and then Save then ask your member to clear the browser they used and try again.