MS sharepoint online: cannot add myself as term store administrator

MS sharepoint online: cannot add myself as term store administrator

I got error like , error add user

so I logged a ticket with MS online support

eventually found out the username need be selected twice, very vague, when I entered the user email address, need click again, then down the right-hand bottom of the screen, I see another selection screen pop-up, select Mike X [tenant],

things are weird when it is all online

here is the troubleshooting log

3:01 p.m. Connecting...
3:01 p.m. Connected. A support representative will be with you shortly.
3:01 p.m. Support session established with Jack Soft.
3:02 p.m. MikeX: Hello Jack Soft, how are you?
3:02 p.m. Remote Control started by Jack Soft.
3:02 p.m. Jack Soft: Good
3:02 p.m. Jack Soft: How are you
3:02 p.m. Jack Soft: I can see the screen
3:02 p.m. MikeX: not too bad
3:02 p.m. MikeX: ok, do u want me to login to the MS portal?
3:02 p.m. Jack Soft: Yeah
3:03 p.m. MikeX: this is our company GoldMine's account
3:04 p.m. Jack Soft: Ok, let's go to term store
3:04 p.m. MikeX: I added my slef as global admin a while ago, now I am fiddling with the sharepoint to prepare for an exam
3:06 p.m. Jack Soft: Here is the thing
3:06 p.m. MikeX: what's the trick?
3:06 p.m. Jack Soft: the term store reads user's name from both portal and sharepoint
3:07 p.m. Jack Soft: once the user's email address is add, it will have two selections
3:07 p.m. Jack Soft: select both email adress and user's name is OK
3:08 p.m. MikeX: ok, that's great.
3:08 p.m. MikeX: I will have to fiddle more later
3:08 p.m. MikeX: thanks for the help.
3:08 p.m. MikeX: you can close this case now. Kind regards, Mike Shen
3:09 p.m. Jack Soft: Sure. Then I will send you a summary and close the case
3:09 p.m. MikeX: ok, great
3:09 p.m. Jack Soft: Thank you for your time.Mike. Have a nice day.
3:09 p.m. MikeX: u 2
3:09 p.m. Jack Soft: See you.
3:10 p.m. Jack Soft has ended the session.
3:10 p.m. Remote Control by Jack Soft stopped.