@Moderator_1
Thank you for the reply. This is an ease-of-use question not an application working question.

Please see the following steps to reproduce the issue.

1. Login as new user to the site.
2. Enable TOTP
3. Log out and Login as the same user
4. Clicking on TOTP site shows a second login to the site asking client id and mpin.

Core issue: UX issue Why are you asking me for a login again?
Is the user not validated on the main site?
If yes, why ask for client id and mpin here while you allow email and pass on the main site?

Hope you see the subtle question here. It works as it stands, but not smooth.

@Moderator_1
Clearing the browsing cache allows me to select a category and submit a new ticket.
That being said, the cache is set by the site itself and some other page in the same forum site is corrupting the cache. We can close this issue now, but it is a deeper issue and I predict, will manifest as some other cache corruption issue as the root cause is not addressed.

In the forum, when creating a new topic from laptop/desktop in MS-EDGE browser, we are not able to select the category. Clicking on dropdown gets list of categories but selecting a category does not populate the box and enable us to submit the issue/question.

I have enabled totp already but had failed to note the token completely.
When I tried to login with my email address, the <enable totp> section of the site
first asks for mpin instead of password and when entered, gives an error message o 'try again later' rather than forcing us to enter client id.

Workaround: Use Client ID instead of email address and mpin

Ideal method of working:
Allow either email, client id or phone no as 'userid'
Allow password as the password and not mpin