Hi Victor,
Please recheck below configurations
--> Created RFC destination of type 3
--> Create Port in IDX1 in the format of SAP+Sysid (Sysid of ECC) and assign RFC destination created
If the port created in IDX1 is in the format of SAP+SysId then automatically IDoc metadata will be imported into IDX2.If not, as suggested please delete the metadata and reimport again by selecting create button
Thanks