J-Web login with radius authentication failed while SSH worked

J-Web login with Radius authentication failed while SSH login worked for the same user 

SRX would validate the username with a need to be matched exactly with Junos CLI username pattern for jweb users only 

Otherwise, even when the user is authenticated by Radius Server, J-Web would keep spinning without processing further and user wont be able to access the device through j-web.

J-Web trace might report invalid username error as referenced below : 

                     [time-stamps] httpd_gk_mgd_connect_cb: gk.gk_url=/launchpad/lpad.php gk.gk_url_query=example(a),httpd_gk_data.jail=/jail
                     [time-stamps] isValidEntityValue: username is invalid

Here is the guide for reference: 

https://www.juniper.net/documentation/us/en/software/junos/user-access/topics/topic-map/junos-os-user-accounts.html
Username (Required): Name that identifies the user. It must be unique. Avoid using spaces, colons, or commas in the username. The username can include up to 64 characters.
Note: rackets, special charactors like "~!@#$%^&*()" are not valid either

You may verify further from CLI configuration mode to see if it gives errors: 

root@jlab-srx380# set system login user example(a)
                                                                               ^
invalid value.

root@jlab-srx380#set system login user 'example(a)'
                                                                               ^
invalid value.

root@jlab-srx380# set system login user "example(a)"
error: user-name: 'example(a)': Must contain characters (alphanumerics, underscores or hyphens) beginning with an alphanumeric or an underscore character.
error: statement creation failed: user

The same restriction applies even if the user name is defined over the radius server and during authentication j-web login trial however ssh can still works with no issues.