Can't invite old account to clan?

Hello, as the title says, I cannot invite my old account which is my main onto a "dummy" clan that I have on a relatively new alt. My main's rank is 28 and my alt that hosts the clan is 5. I have the option of inviting another person to the clan, but not my main. Does anyone know why?

For clarification, by "can't invite" i mean that the "Apply to clan/clan invite" button isnt there/greyed out.

Bump, still concerned about the issue...

Iirc you can only invite people if they don't have a clan.

Did do that,as you can see in the pic afterall how would i invite myelf anyway, on an alt

if it helps, the alt im inviting myself to is dos because brd sucks

You can't add someone from different union

That's pretty bs, but that would be the answer i have to accept i guess. Thanks!