Can't send "query" request - 400 error (SELECT * FROM ... WHERE DisplayName LIKE ...)

I have the following query:

  const selectStatement = `SELECT * FROM Customer WHERE DisplayName LIKE '%MFM 58%'`; // does NOT work!
  // const selectStatement = 'SELECT * FROM Customer'; // works just fine! :)
  const resp = await oauthClient.makeApiCall({
    url: `https://sandbox-quickbooks.api.intuit.com/v3/company/${realmId}/query?query=${selectStatement}&minorversion=65`,
    method: 'GET'
  });

This does NOT work!

I always get a 400 Bad Request - but everything is just fine! NO problems with the auth, because the following selectStatement works just fine: selectStatement = 'SELECT * FROM Customer' ... so what gives? I don't see what is wrong with my call!

Start at oauthClient.makeApiCall and reproduce the two query URLs shown in the issue, comparing the working SELECT request with the LIKE request. Inspect the resulting request and 400 response to determine where the two forms diverge; done means the LIKE query has a confirmed cause and a verified resolution or clear explanation.