Can't login ORA-28031: maximum of 148 enabled roles exceeded I can't login - and receive the error code above. How do I fix this?
to let the user connect you need revoke some roles from the user 

see discussion about here: AskTom

https://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1565923300346644029

the discussion about parameter MAX_ENABLED_ROLES that used to limit max count of roles to 150 roles. the parameter is marked as deprecated but as the discussion says it still had some value for limit


  It is deprecated because they are currently maxing it out (just like
  maxtrans is deprecated - but still "exists", it is 255 no matter what
  you set it to)
  MAX_ENABLED_ROLES 


Range of values 0 to 148



  deprecated
  
  MAX_ENABLED_ROLES specifies the maximum number of database roles that
  users can enable, including roles contained within other roles. The
  actual number of roles that users can enable is 2 plus the value of
  MAX_ENABLED_ROLES, because each user has two additional roles, PUBLIC
  and the user's own role.