About Aero Continente being banned from the US

[A318]

I just read in the latest news that Aero Continente is banned from the US.
Since there is not much information and just a guess it has to do with safety issues I wonder is anybody has more information about it?
Aero Continente excists for more then 10 years now and never had huge mishaps.
Only issue happened last year when a landing gear collapsed which only damaged the gear.
So I wonder, which safety issues caused this bann???

Greetz,

Erwin