IF statement not working (dependent on checkbox field)

IF statement not working (dependent on checkbox field)

I am not sure why the 2nd IF statement is not working... The first one triggers an email to be sent, as well as the third one, but the second one does not. 

if((input.Type_of_Sign.toString()  ==  "In-Store")  &&  (input.Type_of_Sign.toString()  !=  "Event/Trade Show"))
{
sendmail
[
from:zoho.adminuserid
to:zoho.adminuserid
subject:"New signage request"
message:"Signage request details:<br />\n<br />\nName:&nbsp;" + input.Name + "<br />\nDepartment:&nbsp;" + input.Department + "<br />\nDate:&nbsp;" + input.Date_field + "<br />\nType of Sign:&nbsp;" + input.Type_of_Sign + "<br />\nIn-Store Signs requested:&nbsp;" + input.In_Store_signs + "<br />\nDetail of Sign:&nbsp;" + input.Detail_of_Sign + "<br />\nDetail of copy:&nbsp;" + input.Provide_Detail_of_Copy + "<br />\nNavision SKU(s):&nbsp;" + input.Navision_sku_s + "<br />\nProduct Link (if applicable):&nbsp;" + input.Product_link_if_applicable + "<br />\nFile attached:&nbsp;" + input.Attach_file_for_details_and_or_image
content type:HTML
]
}
if((input.Type_of_Sign.toString()  ==  "In-Store")  &&  (input.Type_of_Sign.toString()  ==  "Event/Trade Show"))
{
sendmail
[
from:zoho.adminuserid
to:zoho.adminuserid
subject:"New signage request"
message:"Signage request details:<br>\n<br>\nName:&nbsp;" + input.Name + "<br>\nDepartment:&nbsp;" + input.Department + "<br>\n<br>\n<br> Date:&nbsp;" + input.Date_field + "<br>\nType of Sign:&nbsp;" + input.Type_of_Sign + "<br>\nIn-Store Signs requested:&nbsp;" + input.In_Store_signs + "<br>\nEvent/Trade Show signs requested:&nbsp;" + input.Event_Trade_Show_signs + "<br>\nDetail of Sign:&nbsp;" + input.Detail_of_Sign + "<br>\nDetail of copy:&nbsp;" + input.Provide_Detail_of_Copy + "<br>\nNavision SKU(s):&nbsp;" + input.Navision_sku_s + "<br>\nProduct Link (if applicable):&nbsp;" + input.Product_link_if_applicable + "<br>\nFile attached:&nbsp;" + input.Attach_file_for_details_and_or_image
content type:HTML
]
}
if((input.Type_of_Sign.toString()  ==  "Event/Trade Show")  &&  (input.Type_of_Sign.toString()  !=  "In-Store"))
{
sendmail
[
from:zoho.adminuserid
to:zoho.adminuserid
subject:"New signage request"
message:"New signage request details<br />\n<br />\nName:&nbsp;" + input.Name + "<br />\nDepartment:&nbsp;" + input.Department + "<br />\nDate:&nbsp;" + input.Date_field + "<br />\nType of Sign:&nbsp;" + input.Type_of_Sign + "<br />\nEvent/Trade Show Signs requested:&nbsp;" + input.Event_Trade_Show_signs + "<br />\nDetail of Sign:&nbsp;" + input.Detail_of_Sign + "<br />\nDetail of copy:&nbsp;" + input.Provide_Detail_of_Copy + "<br />\nNavision SKU(s):&nbsp;" + input.Navision_sku_s + "<br />\nProduct Link (if applicable):&nbsp;" + input.Product_link_if_applicable + "<br />\nFile attached:&nbsp;" + input.Attach_file_for_details_and_or_image
content type:HTML
]
}

Type of Sign field is a checkbox field, which allows multiple things to be checked off. I am trying to trigger an email to be sent when both of the checkboxes are ticked off. 

Thank you in advance!