O2 Reject my Handy Bestellung

Hello,

I have tried twice, both through the website and onsite, to purchase an iphone to pay in 24 months and my order got rejected due to Solvency Check , could you please tell me what is wrong?

I have no debts, I have this bank account for more than 3 months and also my salary is very high for a 42 euros phone.

I have no idea what else should I prove to be able to make this purchase? or either I would cancel my plan and buy a full package with another provider.

Could you please check?

Thanks!