So make sure "Retract on Layer Change" is enabled; and try increasing the retraction amount if necessary.

Here my settings:

[filament:eSUN PLA]
bed_temperature = 55
bridge_fan_speed = 100
cooling = 0
disable_fan_first_layers = 1
extrusion_multiplier = 0.935
fan_always_on = 1
fan_below_layer_time = 60
filament_colour = #000000
filament_diameter = 1.75
first_layer_bed_temperature = 55
first_layer_temperature = 205
max_fan_speed = 100
min_fan_speed = 100
min_print_speed = 10
slowdown_below_layer_time = 30
temperature = 205

[presets]
filament = eSUN PLA.ini
print = Medium.ini
printer = 40 4.ini

[print:Medium speed]
avoid_crossing_perimeters = 1
bottom_solid_layers = 4
bridge_acceleration = 0
bridge_flow_ratio = 1
bridge_speed = 20
brim_width = 0
complete_objects = 0
default_acceleration = 0
dont_support_bridges = 0
external_fill_pattern = rectilinear
external_perimeter_extrusion_width = 0
external_perimeter_speed = 80%
external_perimeters_first = 0
extra_perimeters = 1
extruder_clearance_height = 20
extruder_clearance_radius = 20
extrusion_width = 0
fill_angle = 45
fill_density = 0%
fill_pattern = rectilinear
first_layer_acceleration = 0
first_layer_extrusion_width = 200%
first_layer_height = 0.3
first_layer_speed = 20%
gap_fill_speed = 40
gcode_comments = 0
infill_acceleration = 0
infill_every_layers = 1
infill_extruder = 1
infill_extrusion_width = 0
infill_first = 0
infill_only_where_needed = 0
infill_overlap = 15%
infill_speed = 70
interface_shells = 0
layer_height = 0.3
max_print_speed = 80
max_volumetric_speed = 0
min_skirt_length = 10
notes =
only_retract_when_crossing_perimeters = 0
ooze_prevention = 0
output_filename_format = [input_filename_base].gcode
overhangs = 1
perimeter_acceleration = 0
perimeter_extruder = 1
perimeter_extrusion_width = 0
perimeter_speed = 60
perimeters = 2
post_process =
raft_layers = 0
resolution = 0
seam_position = aligned
skirt_distance = 2
skirt_height = 1
skirts = 1
small_perimeter_speed = 70%
solid_infill_below_area = 70
solid_infill_every_layers = 0
solid_infill_extruder = 1
solid_infill_extrusion_width = 0
solid_infill_speed = 80%
spiral_vase = 0
standby_temperature_delta = -5
support_material = 0
support_material_angle = 0
support_material_contact_distance = 0.2
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0
support_material_interface_extruder = 1
support_material_interface_layers = 3
support_material_interface_spacing = 0
support_material_interface_speed = 75%
support_material_pattern = honeycomb
support_material_spacing = 10
support_material_speed = 40
support_material_threshold = 10
thin_walls = 1
threads = 8
top_infill_extrusion_width = 0
top_solid_infill_speed = 30
top_solid_layers = 4
travel_speed = 130
xy_size_compensation = 0

[printer:40 4]
bed_shape = 0x0,200x0,200x200,0x200
before_layer_gcode =
end_gcode = M104 S0 ; turn off temperature\nG28 X0  ; home X axis\nM84     ; disable motors\n
extruder_offset = 0x0
gcode_flavor = reprap
layer_gcode =
nozzle_diameter = 0.4
octoprint_apikey =
octoprint_host =
pressure_advance = 0
retract_before_travel = 1.5
retract_layer_change = 1
retract_length = 4
retract_length_toolchange = 10
retract_lift = 0
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 40
start_gcode = G28 ; home all axes\nG1 Z5 F5000 ; lift nozzle\n
toolchange_gcode =
use_firmware_retraction = 0
use_relative_e_distances = 0
use_volumetric_e = 0
vibration_limit = 0
wipe = 0
z_offset = 0