Hi Tomas,
Please check the verification profile of the transfer order and also check the setting for the verification profile. it seems the value is maitained as 3 hence system is checking with the EAN Code. if you want to enter the material code then the value in verification profile shoule be 1
Check the value maintained in the Mat. Src. Bin, or Mat Dest Bin (this depend on the verification profile which you activated at what level source or destination)