To address this issue, you can use one of the following options.
You can set this behavior at the user level, but changing the 'Allow single factor' value to 'Enabled'
This will allow this particular user to log in using LDAP Password + OTP, OTP only, or LDAP Password only.
Please note that the LDAP Password only option will work for TOTPRadius v 0.2.7 or newer.
Starting from TOTPRadius v0.2.9, it is also possible to allow single factor logins from a trusted IP range. This setting is called 'Trusted IP Configuration' and can be set in the Settings → Advanced Settings section.
The value is expected in CIDR format. To disable this functionality, set the value of this field to 'none'.