"the timing hasn't been good"
 

When two people haven't been able to sync up the way they want (meet, talk on the phone, etc) because each one's personal schedules gets in the way, we sometimes say " The timing has been off" or "The timing hasn't been good."

What's an equivalent expression in Spanish?

In Spain I would probably say something like,

"No hemos podido coincidir..."
"No hemos podido arreglárnoslas para quedar - vernos..."
"No hemos podido quedar"
"No hemos podido vernos por culpa de nuestros horarios"
"Nuestros horarios no se han coordinado"...

More formally,
"Nuestras agendas no han coincidido"

"No ha habido oportunidad..."

Saludos.