Only reason I can see from the rules would be that your employer offers less that the minimum salary (kollektivvertrag) for your position.
See below for EU Blue Card Germany, Non EU Citizen, No Degree, No German based training, WITH ICT(information computer technology) experience will qualify.
See below for EU Blue Card Germany, Non EU Citizen, No Degree, No German based training, WITH ICT(information computer technology) experience will qualify.
http://www.bluecard-eu.de/eu-blue-card-germany/work-permit.h...
What "WORD FOR WORD" in German is stated on your VISA rejection cause in BOTH CASES?