hfss slotline port size

I am trying to simulate a simple slotline in Duroid 6010 substrate (h= 1.524mm, e_r = 10.8 ) from 1 GHz to 5 GHz. The width of slotline is w = 0.1mm which gives about 50 Ohm Z0. According to the rule of thumb, the port width is 8*w and height is 5*h (2h above substrate and 2h below substare).
I start with the port only simulation, and it terminated with error message like:
"Port-only solution, process abc3d: The frequency specified for this problem is too low. The solution may not be converged. Check the frequency and material properties for this problem".
I do want to simulate it from 1 - 5 GHz, thus I have to stick with these frequency, and I can not find anything wrong with my materail property. Could someone help me to take a look my slotline HFSS simulation setup and give me some suggestion?
Your advice is highly appreciated!

you may reduce the size of port.

I reduce the port size and tried seveal different sizes , even down to its minimum (width = 3W and height = 3h).
It seems thet go through the initial mesh and lambda-Refine mesh steps, when they get to the solving ports steps, they are all terminated with same error message I posted before.
I am wondering if this error is related to the mesh. Do I need to do some maunal mesh operation on certain surface based on this slotline design?
Thanks!

Take a look in the on-line help in the section regarding impedance calculation. There is cogent information there.

Hello, Azulykit, Thank you for your reply. I guess you must mean something when you suggest me to take a look the impedance calculation. I did go through the related sections in on-line help of HFSS, I realize I need use Zpv to calculate the port impedance for soltline (Actually that is what I did in the port setup), but I don't know whatelse is helpful for my case. I guess I must miss your points, thus could you please make it more specific so that it is easy for me to look into it? I am stuck here now and desperately need help to solve this problem. Thank you in advance!