Thanks. It is much more clear now what you are trying to achieve.
The problem is that you are performing all these operations in the sub-flowsheet. Hysys does not recognize these changes and it is unable to solve the model in the main (parent) flowsheet. If the main flowsheet cannot be solved, you will be seeing blank streams in the sub-flowsheet. So everything has to be done in the main flowsheet.
Start with a template called "Refluxed absorber", which is basically a distillation column without reboiler. Then add a heat exchanger separately from the column, and start connecting streams in the way they should be arranged for given reboiler type. Example for one configuration (reboiler with baffle in the column bottom) is shown in the reference thread in my previous post. You may need some recycle streams to have the model running.
What I do not understand is that you are apparently using two exchangers (reboilers) in series. This will never work in reality, no matter what the model says. The reasons are of a practical nature:
1) It is impossible to arrange inlet and outlet piping for this exchanger/reboiler system to have it working properly.
2) Process outlet from the 1st reboiler/exchanger will be two-phase stream entering the 2nd reboiler. This is physically impossible concept.
Instead, what you can do, is to use a single exchanger as the reboiler, with the hot external stream (currently represented as EE1 energy stream, but you can replace a Heater unit operation with the Exchanger unit operation and provide material streams on the inlet and outlet sides of this exchanger).