After moving to a new server, many function of my apps are not working. It works again after installing some PHP extension, but this one is still not working. I never changed anything in my app because I'm not good at coding.

<img src="http://'.$_SERVER['HTTP_HOST'].'/gallery/'.base64_encode('../media/'.md5($cm.'manf').'/'.$t['photos']).'/'.$cm.'/'.$t['name'].'.png"/>

Image is not showing on my page. Honestly, that base64_encode value is correct. I've tried to decode its value on https://www.base64decode.org/ and the result is correct.
The problem is: why that value is not rewritten to img url source? Still trying to figure it out, maybe the problem is not in the code, but on my web-server or something else.
Any advice is very appreciated.