Can't reinforce Altars

Sup guys.
So, in the quest "Alter-Nate Diplomacy", our clan captures altars. Other members try to reinforce the leader to get more points, but for sone reason, we cant. It's just gray and says "A rally join march must contain troops to reinforce with"
But the thing is, you cant add troops.
We tried everything.
More rally troop research, sending 1 troop as rally leader to have more room for other members, joining before the rally leaves. It just wont let any1 join exept the rally leader.
How does this work?

BTW, clan chest is lvl9 if its important.

Thx