Good morning, I have corrected your text. There are many ways of saying the same thing in the text provided. My suggestions improve the text provided by you, but do not represent the only correct way of saying what you wish to convey. I chose to adhere as closely as possible to your original text.
The first payment is supposed to be this month. However due to some of the management still being overseas and one of them being sick, the signing of the credit agreement will have to exceed the payment schedule that has been set, so the first payment will have to take place a month late.