ECO2M:run is not convergent

Dear TOUGH community users,

      I am using T2WELL/ECO2M to simulate the injection of CO2 into the aquifer, building a model of 0~-900 m (3D) and the aquifer is located in-750m~-800m.

        Assuming that the aquifer is initially completely filled with water and the mass fraction of Nacl is 0, liquid CO2 is injected from the well head to the aquifer by means of isoenthalpy injection (8 MPa, 25 ℃, and the corresponding specific enthalpy is 0.263205E+06 by another program).

      In the input file, I separately added a virtual wellhead unit * bA 1 (located on the surface), the unit volume is set to infinite (1.0000E+52), the distance from its connection to the interface with the next unit is set to 1.0000E-15 (CONNE), and its initial state is set to 2 (initially filled with liquid CO2) in the INCON data block.

       I wonder which parameter of the input file is set incorrectly and the operation cannot be converged. Will the connection order of CONNE also affect it? I urgently need your help , thank you very much!