PHP variable = get_the_post_thumbnail_url outputting without slashes

Replacing the line with below line may solve the issue.

$text_slider_content .= '<div class="text_slider_testimonial" style="background-size: cover; background-image: url('. $text_slider_testimonial_img .');">';

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)