[Koha] How to hide the OPAC "Cover Not Available" message?

Good night, How to hide the OPAC "Cover Not Available" message? I enabled "OPACAmazonCoverImages" and "OPACLocalCoverImages" to insert images that are not on Amazon. When he loads the image from Amazon, the message "Cover Not Available" also appears. I would like to remove this message when he retrieves the image from Amazon. Thanks, Victor