Can't sign into my profile even tho I have my email and password

My password was complex. I don't think the changes MS made a month ago caused the issue. I used a link they gave me to reset my password and using IE is mandatory for the password change to work. The combination seems to be the answer. Which I think the
link above was the same as what I used from MS and IE, then selected "I know my password and Microsoft account, but can't sign in" option and changed my password. (Even tho I could login) The system logged me out and then I used the new password and it worked.
I later signed into the Xbox console and was able to download my profile.

Yes, i still have my old xbox and all the apps. Luckily, i can still play WOT on my old xbox. I wanted to upgrade the reason i purchased the new xbox. I am using the same original email and password when i created my profile into the new xbox including this
one to be able to converse with you. My dilemma is i cannot undo my mistake of using “Bludragun313”as my gamertag on the new xbox because the new xbox would not allow me to use my gamertag”” even tho i am using the same email and the same password
.

i can go online and see my account for “bluedragun13” still active again using my original email and password to sign in.

yes - i have a family gold membership and can sign in with my son's profiles no problem

I don't know my wife's password so can't test hers but it is asking me to input email address and password as with my own.

I can't sign either even if I know my email and password it still won't let me sign in it just says error code 0x87DD0006

Yes, that's the problem: I can't download my old profile because I can't reset the password. I don't even know if that email is still "alive".