Hi Sahil,
I confirm this is happening just for one user.
This is oxauth.log extract when user login:
"2019-04-18 08:03:13,380 ERROR [qtp804611486-16] [org.xdi.oxauth.service.AuthenticationService] (AuthenticationService.java:314) - Failed to authenticate dn: inum=@!CCA2.5C64.BBC8.BEB6!0001!069D.2040!0000!18C1.BDDF,ou=people,o=@!CCA2.5C64.BBC8.BEB6!0001!069D.2040,o=gluu"
This is oxauth_script.log
"2019-04-18 08:06:48,277 INFO [qtp804611486-15] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Authenticate for step 1
2019-04-18 08:06:48,304 INFO [qtp804611486-15] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Authenticate for step 1 . There is no OTP enrollment for user 'emanuele.dangelo@oss.srl'. Changing otp_a uth_method to 'enroll'
2019-04-18 08:06:48,304 INFO [qtp804611486-15] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Authenticate for step 1 . Setting count steps: '3'
2019-04-18 08:06:48,305 INFO [qtp804611486-15] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Authenticate for step 1 . otp_auth_method: 'enroll'
2019-04-18 08:06:48,306 INFO [qtp804611486-15] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Gep page for step 2. ot p_auth_method: 'enroll'
2019-04-18 08:06:48,369 INFO [qtp804611486-10] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Prepare for step 2
2019-04-18 08:06:48,370 INFO [qtp804611486-10] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Prepare for step 2. otp _auth_method: 'enroll'
2019-04-18 08:06:48,371 INFO [qtp804611486-10] [org.xdi.service.PythonService$P ythonLoggerOutputStream] (PythonService.java:239) - OTP. Prepare for step 2. Pre pared enrollment request for user: 'emanuele.dangelo@oss.srl'
"
In the attachment you can see the page displayed to the user after login