We cannot convert the value null to type Logical.

Hi there,

I am trying to create a conditional column based on another column. When I created a conditional column, I got an error "Expression. Error: We cannot convert the value null to type Logical". I am not sure where am I making the mistake. Below is the description of the columns:

First I created a column in power query which looks like as follow:

Customer Notification (days) =

if [InterruptionType] ="1" then null else
if Date.Year([#"Cancelled Date (NZST)"]) = 1900 and [InterruptionType] = "2" then List.Max({[#"Notice to Retail Consumer (days)"], [#"Notice to Direct Bill Consumer (days)"]})
else
if Date.Year([#"Cancelled Date (NZST)"]) = 1900 and [InterruptionType] = "3" and Date.Year([#"Notified Interruption Date Time (NZST)"]) <> 1900 then List.Max({[#"Notice to Retail Consumer (days)"], [#"Notice to Direct Bill Consumer (days)"]}) else null

and it looks like as follow:

Then I created a conditional column using the following logic:

However, it throws error of "Expression. Error: We cannot convert the value null to type Logical.

Could anyone help me where I made the mistake?