Images missing, in tickets, on customer facing end

Images do not show at all on customer facing site:

Image SRC shows as (incorrect):

"/portal/mail/ImageDisplayZSupport?supzgid=1588ac18de7965a4a48d23f14fc053d4&na=1156310000000002002&nmsgId=1578324382286000001&f=1.png&mode=inline&cid=0.28873910240.7326964232281928898.16f7b76d00e__inline__img__src&"

However they show find on admin facing site:

Image SRC shows as (correct):

"https://desk.zoho.eu/mail/ImageDisplayZSupport?supzgid=1588ac18de7965a4a48d23f14fc053d4&na=1156310000000002002&nmsgId=1578324382286000001&f=1.png&mode=inline&cid=0.28873910240.7326964232281928898.16f7b76d00e__inline__img__src&"

Please see screenshots.

Please fix this! This bug has been there since October at least!