INNER JOIN Query - Conversion Error

Trying to run a query to get total number of direct mail campaigns by company. Would like the totals to be (1) total number of direct mail campaigns (there are 2 types) (2) total number of direct mail campaigns type direct mail (3) total number of direct mail campaigns type publication

Below is the query I put together with INNER JOIN:

SELECT Agency.PrimaryAgencyName, COUNT(Distinct Campaigns.DirectMailID) AS TotalCampaigns, COUNT(Distinct DirectMail.Type) AS TotalDirectMail

FROM Agency
INNER JOIN (Clients
INNER JOIN (Campaigns
INNER JOIN DirectMail
ON DirectMail.DirectMailID = Campaigns.DirectMailID)
ON Clients.ClientID = Campaigns.CampaignID)
ON Agency.AgencyID = Clients.AgencyID

GROUP BY Agency.PrimaryAgencyName, DirectMail.Month, DirectMail.Type
ORDER BY Agency.PrimaryAgencyName

When I run the query, I recent the below error:

Msg 245, Level 16, State 1, Line 1
Conversion failed when converting the nvarchar value '1683 1-15017' to data type int.

The value mentioned in the above error message is the ClientID.

Below are the tables for reference (bold for entity name and underline for PK) and datatypes

Agency
AgencyID - nvarchar(255)
PrimaryAgencyName - nvarchar(255)

Campaigns
CampaignID- int
ClientID- nvarchar(255)
DirectMailID- nvarchar(255)

Clients
ClientID - nvarchar(255)
AgencyID - nvarchar(255)

DirectMail
DirectMailID - nvarchar(255)
Campaign - nvarchar(255)
Type - nvarchar(255)
Month - float