I forgot my old emai ID

hello i have old mail my apple watch 3 connected old mail, but i forgot password when i connect this watch new iphone he whant old icloud password and mail.... i have phone number and mail i forget my password ... l*******@icloud.com and i have number registred this mail 5999xxxxxx please help... this old mail turn on find my watch i forgot password and i cant to turn off

[Edited by Moderator]