Trump and Ukraine do not have a ‘very close relationship.’
Under Obama, America and Ukraine has a very close relationship.
Since Trump came to power, he has blatantly favoured Russia, which is funding and supplying the rebels in eastern Ukraine.
Zelensky, since he took power in April, has been desperately trying to get a show of support from the US for his efforts to end the war in eastern Ukraine.
But Trump has humiliated him - Zelensky has been threatened with the withdrawal of military aid, hasn’t got the state visit to the White House he wanted, and has instead been embroiled in the impeachment scandal leading to the exposure of his embarrassing phonecall with Trump.