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Fatal error: Uncaught Exception: FPDF error: Some data has already been output, can't send PDF file in C:\wamp64\www\gmwindows\fpdf\fpdf.php:271 Stack trace: #0 C:\wamp64\www\gmwindows\fpdf\fpdf.php(1063): FPDF->Error('Some data has a...') #1 C:\wamp64\www\gmwindows\fpdf\fpdf.php(999): FPDF->_checkoutput() #2 C:\wamp64\www\gmwindows\objects\pinvoice.php(244): FPDF->Output() #3 {main} thrown in C:\wamp64\www\gmwindows\fpdf\fpdf.php on line 271