  In this paper, we study a particular type of inflation by using non-local
Friedman equations that are somehow derived from the zero levels of string
field theory and express a tachyonic action. Then, we challenge it by further
refining de Sitter (dS) swampland conjecture (FRdSSC) monitoring. Therefore, we
investigate some quantities, such as potential and Hubble parameters. We also
consider slow-roll parameters to examine quantities such as the scalar spectrum
index and the tensor-to-scalar ratio. Using straightforward calculations, we
investigate this model from the swampland conjecture perspective in terms of
the cosmological parameters, i.e., ($n_s$), ($r$), and observable data such as
Planck 2018, by constructing some structures such as $(c_1,2-n_s)$ and
$(c_1,2-r_s)$. Then, we make a new restriction for this conjecture as
$c_12c_22$ and get a limit for this model in the range $c0.0942$. We find this
inflationary model is strongly in tension with the dS swampland conjecture
(dSSC), i.e., $c_1=c_2 \neq \mathcal{O}(1)$. So, we shall challenge it with the
FRdSSC, which has some free parameters, viz., $a,b>0$, $a+b=1$, and $q>2$. By
setting these parameters, we examine the compatibility of the mentioned
conjecture with this inflationary model. Finally, we infer from this string
field inflation model that it satisfies the FRdSSC with the constraint of its
free parameters $a$, $b$, and $q$.
