Difficulty in fitting convoluted function

ROOT Version: 6.24/00
Platform: 5.17.12-100.fc34.x86_64
Compiler: gcc version 11.3.1 20220421 (Red Hat 11.3.1-2) (GCC)

Hi RooFit experts,

I am trying to fit data ( test.txt) with a gaussian convoluted with exponential function using the macro attached below.

gexp_conv.C (2.2 KB)

However, neither I am able to see the correct distribution as expected from the data nor the fit.
Can you please help? This is my first time with RooFit!

Any help is highly appreciated.

Thanking you.

With best regards,

Ajay

I think @moneta can help you.