email notification 30 days before expiration date

[AC8]

Hi all, 

Goal: receive an email notification 30 days before the expiration date. 

So, I've created a column "Expiration Date", and I want to trigger the email only for those items which will expire within 30 days. And I need the flow to check this every single day, but only send emails 30 days before for those items that match this rule. 

I have the following: 

addDays(utcNow(), -30)

Error: 

Unable to process template language expressions for action 'Condition_2' at line '1' and column '15047': 'The template language function 'less' expects two parameter of matching types. The function was invoked with values of type 'Null' and 'String' that do not match.'.

I'm totally not an expert on this. Could someone please help me? 

Many thanks!

[tom_riha]

Hello @AC8 ,

it would be better to filter the items directly in the 'Get items' using a Filter query than checking all the items. I wrote a post on building basic reminder flow that might help you to build such a flow.