i have followed the steps to signal subscription but when i select payment method the page goes blank with "this page cannot be displayed " https://www.mql5.com/en/accounting/public/mql5
my account is mt4 real account
You need to contact the Service Desk.
Follow these instructions: https://www.mql5.com/en/forum/189731
Maybe you mean of payment is stuck for some reason, so try to deposit the appropriate amount in your MQL5 account first.