I get the warning "Inside surface heat balance did not converge"

edit

I'm a student at the university of Antwerp and I'm writing a thesis on green walls.

Currently, there is no green wall in Energyplus so what I intend to do to simulate green walls is the following. - I use the class SurfaceProperty:ExteriorNaturalVentedCavity to add a baffle to an exterior wall - I use the class SurfaceProperty:HeatBalanceSourceTerm to add heat fluxes to said baffle - I use EMS to actuate a schedule which my program overwrites each timestip with a program I write

The program itself is used to calculate the shortwave and longwave radiation, convective and latent heat fluxes (in a green wall).

I always get an error saying "Inside surface heat balance did not converge" which I can't seem to fix, I already looked at other related questions similar like this one:

https://unmethours.com/question/30345...

https://unmethours.com/question/17156...

but it doesn't fix it. the problems arise with the equation of the convective heat flux. When I calculate the term:

phi_conv_f = (2*LAI*rho_af*Cp/r_a)*(Ta - Tc)  this gives me the error.

LAI = Leaf Area Index

rho_af = air densit

Cp = specific heat of air at constant pressure

r_a = aerodynamic resistance

Ta = outdoor temperature

Tc = Baffle temperature

When I calulate the term: (2LAIrho_af*Cp/r_a) seperately it gives normal numbers and same goes for (Ta - Tc) BUT when I multiply the two terms it doesn't work which doesn't make sense to me.

Am I missing something here, can anybody help please?