Well I applied with my DS1513+ S/N to my xpenology DS3615xs emulation box. Now no problem with uploaded videos. Problem, solved. All you need is a genuine Synology S/N.
Unfortunately, I'm still running my xpenology box as a DS3615xs and not a DS3617xs (preferred configuration), because there is no available Sonarr packages for the DS3617xs (xeon processor) yet.