PDF Error 504 gateway time-out error

Hi ,
i have this issue when try click on pdf to genereate it ,
frappe.utils.print_format.download_pdf Failed to load resource: the server responded with a status of 504 (Gateway Time-out)

Possibly your server did not receive a timely response due to network issues? Is it reproducible, if so which version ( Frappe / ERPNext )

i have this
Installed Apps

ERPNext: v8.1.1 (master)

Frappe Framework: v8.1.1 (master)

maybe it’s the premissons on the server ? do i need to make chmod ?

it was the logo size i used in the letter head in the print format , which i noticed now :frowning:
upload less size image and everything is perfect now