Odoo 11 CE barcode not printing wkhtmltopdf
I have a report to print labels, in it I have:
<img t-att-src="'/report/barcode/?type=%s&value=%s&width=%s&height=%s' % ('Code128', label.default_code, 600, 150)" style="width: 40mm;height: 12mm;horizontal-align: center"/>
On the report the barcode is not printed (a blank area), but if I change the report type to html, then it works fine and the barcode is displayed on the screen, but I need it in PDF of course for printing.
I tried with wkhtmltopdf versions: 0.12.1 , 0.12.3 , 0.12.4 , 0.12.5
What could be wrong?