Error: Decrease a_ini_over_a_today_default in order to start from radiation domination

[astro-20]

Hi all,

I'm working on a cosmological model in which the total energy density of radiation is modified, and hence affects the \Omega_r.
When I run the CLASS code which I modified, I end up with the error:

Omega_r not close enough to 1. Decrease a_ini_over_a_today_default in order to start from radiation domination.

I have been decreasing the a_ini_over_a_today_default down to e-60 but still getting the same error!
I wonder if there is another value I have to change in the ''precision.h'' file in order to solve this problem!
I highly appreciate your response.

Best,
H.