It works fine in 12.0.0 for Microsoft Windows (64-bit) (April 6, 2019).
model1[a_] = ampl Evaluate[PDF[NormalDistribution[x0, sigma], a]];
fit = FindFit[data, model1[a], {ampl, x0, sigma}, a];
g1 = LogPlot[{model1[a] /. fit}, {a, -6.5, 1.5},
PlotStyle -> {Directive[Red, AbsoluteThickness[2.2]]},
PlotLegends ->
Placed[LineLegend[{Style["β=1.0", 16.5,
FontFamily -> "Times New Roman"]},
LegendFunction -> (Framed[#, RoundingRadius -> 5] &),
LegendMargins -> 5], Scaled[{0.15, 0.8}]]];
g = ListLogPlot[data, Axes -> {False, True},
PlotRange -> {{-6.5, 1.5}, {0.01, 1.3}},
AxesStyle -> Directive[Black, AbsoluteThickness[1.0], Dashed],
Frame -> True, FrameStyle -> AbsoluteThickness[1.0],
ImageSize -> 140*72/25.4,
PlotLabel ->
Style["(c) Marginally Eccentric TDE (n=3, e=0.98)",
FontFamily -> "", Black, FontSize -> 18],
FrameTicksStyle ->
Directive[AbsoluteThickness[0.5], FontFamily -> "Times New Roman",
FontSize -> 18],
FrameLabel -> {Style["ϵ/Δϵ", 18,
FontFamily -> "Times New Roman"],
Style["dM/dϵ [\!\(\*SubscriptBox[\(m\), \(*\)]\)/\
Δϵ]", 18, FontFamily -> "Times New Roman"]},
PlotStyle -> {Directive[Darker[Red], AbsoluteThickness[1.5]]}];
Show[{g, g1}, ImageSize -> Large]

data={{-2.99, 0.}, {-2.98, 0.}, {-2.97, 0.}, {-2.96, 0.}, {-2.95,
0.}, {-2.94, 0.}, {-2.93, 0.}, {-2.92, 0.}, {-2.91, 0.}, {-2.9,
0.}, {-2.89, 0.}, {-2.88, 0.}, {-2.87, 0.}, {-2.86, 0.}, {-2.85,
0.}, {-2.84, 0.}, {-2.83, 0.}, {-2.82, 0.}, {-2.81, 0.}, {-2.8,
0.}, {-2.79, 0.}, {-2.78, 0.}, {-2.77, 0.}, {-2.76, 0.}, {-2.75,
0.}, {-2.74, 0.}, {-2.73, 0.}, {-2.72, 0.}, {-2.71, 0.}, {-2.7,
0.}, {-2.69, 0.}, {-2.68, 0.}, {-2.67, 0.}, {-2.66, 0.}, {-2.65,
0.}, {-2.64, 0.}, {-2.63, 0.}, {-2.62, 0.}, {-2.61, 0.}, {-2.6,
0.}, {-2.59, 0.}, {-2.58, 0.}, {-2.57, 0.}, {-2.56, 0.}, {-2.55,
0.}, {-2.54, 0.}, {-2.53, 0.}, {-2.52, 0.}, {-2.51, 0.}, {-2.5,
0.}, {-2.49, 0.}, {-2.48, 0.}, {-2.47, 0.}, {-2.46, 0.}, {-2.45,
0.}, {-2.44, 0.}, {-2.43, 0.}, {-2.42, 0.}, {-2.41, 0.}, {-2.4,
0.}, {-2.39, 0.}, {-2.38, 0.}, {-2.37, 0.}, {-2.36, 0.}, {-2.35,
0.}, {-2.34, 0.}, {-2.33, 0.000995699}, {-2.32,
0.000995699}, {-2.31, 0.}, {-2.3, 0.000995699}, {-2.29,
0.00398279}, {-2.28, 0.0019914}, {-2.27, 0.}, {-2.26,
0.0019914}, {-2.25, 0.}, {-2.24, 0.0019914}, {-2.23,
0.00398279}, {-2.22, 0.00597419}, {-2.21, 0.00497849}, {-2.2,
0.00696989}, {-2.19, 0.000995699}, {-2.18, 0.0019914}, {-2.17,
0.00896129}, {-2.16, 0.00696989}, {-2.15, 0.0109527}, {-2.14,
0.00896129}, {-2.13, 0.00597419}, {-2.12, 0.0129441}, {-2.11,
0.0139398}, {-2.1, 0.0238968}, {-2.09, 0.0119484}, {-2.08,
0.0149355}, {-2.07, 0.0189183}, {-2.06, 0.0129441}, {-2.05,
0.0209097}, {-2.04, 0.0308667}, {-2.03, 0.0288753}, {-2.02,
0.029871}, {-2.01, 0.0398279}, {-2., 0.0458021}, {-1.99,
0.0497849}, {-1.98, 0.052772}, {-1.97, 0.0597419}, {-1.96,
0.0587462}, {-1.95, 0.0896129}, {-1.94, 0.0886172}, {-1.93,
0.136411}, {-1.92, 0.141389}, {-1.91, 0.193166}, {-1.9,
0.215071}, {-1.89, 0.245938}, {-1.88, 0.238968}, {-1.87,
0.227019}, {-1.86, 0.230006}, {-1.85, 0.233989}, {-1.84,
0.231998}, {-1.83, 0.223036}, {-1.82, 0.233989}, {-1.81,
0.235981}, {-1.8, 0.212084}, {-1.79, 0.205114}, {-1.78,
0.207105}, {-1.77, 0.222041}, {-1.76, 0.219054}, {-1.75,
0.229011}, {-1.74, 0.209097}, {-1.73, 0.228015}, {-1.72,
0.229011}, {-1.71, 0.230006}, {-1.7, 0.231002}, {-1.69,
0.231002}, {-1.68, 0.232993}, {-1.67, 0.250916}, {-1.66,
0.259877}, {-1.65, 0.237972}, {-1.64, 0.238968}, {-1.63,
0.238968}, {-1.62, 0.274813}, {-1.61, 0.273817}, {-1.6,
0.314641}, {-1.59, 0.276804}, {-1.58, 0.333559}, {-1.57,
0.304684}, {-1.56, 0.320615}, {-1.55, 0.34252}, {-1.54,
0.346503}, {-1.53, 0.29871}, {-1.52, 0.341525}, {-1.51,
0.405249}, {-1.5, 0.394297}, {-1.49, 0.373387}, {-1.48,
0.429146}, {-1.47, 0.390314}, {-1.46, 0.405249}, {-1.45,
0.440099}, {-1.44, 0.443086}, {-1.43, 0.445077}, {-1.42,
0.488888}, {-1.41, 0.494862}, {-1.4, 0.535686}, {-1.39,
0.5556}, {-1.38, 0.522742}, {-1.37, 0.572527}, {-1.36,
0.582484}, {-1.35, 0.589454}, {-1.34, 0.64123}, {-1.33,
0.63426}, {-1.32, 0.626294}, {-1.31, 0.650191}, {-1.3,
0.681058}, {-1.29, 0.676079}, {-1.28, 0.758722}, {-1.27,
0.783615}, {-1.26, 0.767684}, {-1.25, 0.780628}, {-1.24,
0.772662}, {-1.23, 0.769675}, {-1.22, 0.766688}, {-1.21,
0.804524}, {-1.2, 0.815477}, {-1.19, 0.885176}, {-1.18,
0.848335}, {-1.17, 0.894137}, {-1.16, 0.915047}, {-1.15,
0.945914}, {-1.14, 0.956866}, {-1.13, 0.922017}, {-1.12,
0.946909}, {-1.11, 0.977776}, {-1.1, 0.978772}, {-1.09,
1.04548}, {-1.08, 0.986737}, {-1.07, 1.00167}, {-1.06,
1.0654}, {-1.05, 1.06341}, {-1.04, 1.03951}, {-1.03,
1.05046}, {-1.02, 1.03453}, {-1.01, 1.10722}, {-1.,
1.07038}, {-0.99, 1.04747}, {-0.98, 1.1102}, {-0.97,
1.09726}, {-0.96, 1.02457}, {-0.95, 1.03553}, {-0.94,
1.03752}, {-0.93, 1.02557}, {-0.92, 0.939939}, {-0.91,
1.0425}, {-0.9, 1.0196}, {-0.89, 0.991716}, {-0.88,
0.999681}, {-0.87, 0.958858}, {-0.86, 0.943922}, {-0.85,
0.899116}, {-0.84, 0.921021}, {-0.83, 0.89115}, {-0.82,
0.888163}, {-0.81, 0.961845}, {-0.8, 0.894137}, {-0.79,
0.857296}, {-0.78, 0.857296}, {-0.77, 0.814481}, {-0.76,
0.804524}, {-0.75, 0.775649}, {-0.74, 0.761709}, {-0.73,
0.757727}, {-0.72, 0.763701}, {-0.71, 0.736817}, {-0.7,
0.681058}, {-0.69, 0.693006}, {-0.68, 0.71292}, {-0.67,
0.626294}, {-0.66, 0.668114}, {-0.65, 0.593436}, {-0.64,
0.642226}, {-0.63, 0.570535}, {-0.62, 0.568544}, {-0.61,
0.563565}, {-0.6, 0.529712}, {-0.59, 0.567548}, {-0.58,
0.475944}, {-0.57, 0.459017}, {-0.56, 0.494862}, {-0.55,
0.473953}, {-0.54, 0.451051}, {-0.53, 0.421181}, {-0.52,
0.397284}, {-0.51, 0.405249}, {-0.5, 0.407241}, {-0.49,
0.387327}, {-0.48, 0.360443}, {-0.47, 0.324598}, {-0.46,
0.348495}, {-0.45, 0.338538}, {-0.44, 0.327585}, {-0.43,
0.318624}, {-0.42, 0.310658}, {-0.41, 0.302692}, {-0.4,
0.281783}, {-0.39, 0.289748}, {-0.38, 0.287757}, {-0.37,
0.299705}, {-0.36, 0.276804}, {-0.35, 0.239963}, {-0.34,
0.282778}, {-0.33, 0.236976}, {-0.32, 0.289748}, {-0.31,
0.234985}, {-0.3, 0.255895}, {-0.29, 0.211088}, {-0.28,
0.24992}, {-0.27, 0.200135}, {-0.26, 0.213079}, {-0.25,
0.230006}, {-0.24, 0.221045}, {-0.23, 0.188187}, {-0.22,
0.214075}, {-0.21, 0.259877}, {-0.2, 0.214075}, {-0.19,
0.200135}, {-0.18, 0.204118}, {-0.17, 0.255895}, {-0.16,
0.26386}, {-0.15, 0.19914}, {-0.14, 0.234985}, {-0.13,
0.240959}, {-0.12, 0.24295}, {-0.11, 0.250916}, {-0.1,
0.251912}, {-0.09, 0.188187}, {-0.08, 0.170264}, {-0.07,
0.142385}, {-0.06, 0.0926}, {-0.05, 0.0906086}, {-0.04,
0.072686}, {-0.03, 0.0657161}, {-0.02, 0.0637247}, {-0.01,
0.0448064}, {-1.96752*10^-14, 0.0448064}, {0.01, 0.0438107}, {0.02,
0.0408236}, {0.03, 0.0308667}, {0.04, 0.0288753}, {0.05,
0.0308667}, {0.06, 0.0209097}, {0.07, 0.0159312}, {0.08,
0.0169269}, {0.09, 0.00995699}, {0.1, 0.0179226}, {0.11,
0.0159312}, {0.12, 0.0219054}, {0.13, 0.0119484}, {0.14,
0.00497849}, {0.15, 0.00696989}, {0.16, 0.00995699}, {0.17,
0.00497849}, {0.18, 0.00497849}, {0.19, 0.00696989}, {0.2,
0.0019914}, {0.21, 0.0029871}, {0.22, 0.0029871}, {0.23,
0.00497849}, {0.24, 0.00497849}, {0.25, 0.0019914}, {0.26,
0.000995699}, {0.27, 0.}, {0.28, 0.0029871}, {0.29,
0.000995699}, {0.3, 0.0019914}, {0.31, 0.000995699}, {0.32,
0.000995699}, {0.33, 0.}, {0.34, 0.000995699}, {0.35,
0.000995699}, {0.36, 0.}, {0.37, 0.}, {0.38, 0.}, {0.39, 0.}, {0.4,
0.}, {0.41, 0.}, {0.42, 0.}, {0.43, 0.}, {0.44, 0.}, {0.45,
0.}, {0.46, 0.}, {0.47, 0.}, {0.48, 0.}, {0.49, 0.}, {0.5,
0.}, {0.51, 0.}, {0.52, 0.}, {0.53, 0.}, {0.54, 0.}, {0.55,
0.}, {0.56, 0.}, {0.57, 0.}, {0.58, 0.}, {0.59, 0.}, {0.6,
0.}, {0.61, 0.}, {0.62, 0.}, {0.63, 0.}, {0.64, 0.}, {0.65,
0.}, {0.66, 0.}, {0.67, 0.}, {0.68, 0.}, {0.69, 0.}, {0.7,
0.}, {0.71, 0.}, {0.72, 0.}, {0.73, 0.}, {0.74, 0.}, {0.75,
0.}, {0.76, 0.}, {0.77, 0.}, {0.78, 0.}, {0.79, 0.}, {0.8,
0.}, {0.81, 0.}, {0.82, 0.}, {0.83, 0.}, {0.84, 0.}, {0.85,
0.}, {0.86, 0.}, {0.87, 0.}, {0.88, 0.}, {0.89, 0.}, {0.9,
0.}, {0.91, 0.}, {0.92, 0.}, {0.93, 0.}, {0.94, 0.}, {0.95,
0.}, {0.96, 0.}, {0.97, 0.}, {0.98, 0.}, {0.99, 0.}, {1., 0.}};