How to sign out from 2FA and then again set up the old Apple ID account used with secondary authentication .
( a ) Open system preferences and click on iCloud and click on sign out , a pop up window appears keep the box of iCloud Drive , contacts , calendars , reminders as checked and click on keep a copy , immediately click on stop updating and continue , click on continue with sign out in the next pop up window , the circle rotates .
( b) Enter your 2FA id password and click on continue , circle rotates wait for a while it will stuck and have patience , you can see a red notification 1 over system preferences in the dock , hover the cursor on top menu bar over system preferences you can see SBBOD , it will show preferences error there was an error in iCloud preferences , click on ok .
( c ) Now open system preferences , click on iCloud in the window you will see update Apple ID settings some account services will not be available until you sign again ( having a yellow exclamation mark ) , click on continue .
( d ) It will show update apple settings , some account services will not be available until you sign in again , click on continue .
( e ) Enter your 2FA id password , click on ok .
( f ) Enter your Mac password to continue in the next window so enter your admin password and click on ok , after few moment the pop up error will go away .
( g ) Check the box of keychain and no option button will be shown in front of it as this is 2FA ( note : in secondary authentication id you can see option button ) .
( h ) Check the box of photos and iCloud Drive it will show setting up wait for a while , click on options button every box is checked , click on done also check the box of Siri a pop up window appears do you want to merge your bookmarks and reading list with iCloud , click on ok , the box for safari that was dimmed will turn on , finally all is set .
