Hi,
please try see the tables which shows source and target names.
RSLOGSYSMAP .
RSBASIDOC
source need to have new ecc name EE3.
if you have any data marts dso, you may get issue, try to activate data source by using RS_TRANSTRU_ACTVATE_ALL, enter source system name and select inactive objects.
later you can activate dso or transformations.
For logical mappings, you can check at RSA1--> menu Tools --> there are two below options.
conversion of logical system names
assignment of source system to source system id.
at WE20, please check source system(EE3) need to active.
Thanks.