ERROR: Cannot read properties of undefined (reading 'toString')

Hello everyone, everything good?!

I need help solving a problem I’m having with my flow. I searched here in the community if there were similar problems and found some threads where the problems were related to late versions of n8n. However, my n8n is updated (0.202.1 via Docker).

Anyway, I’m having a problem on the Google Sheets with the Lookup operation. When I run the Google Sheets node the message “ERROR: Cannot read properties of undefined (reading ‘toString’)” appears.

Thought I’d put my workflow here, but I’m not sure how it works for sure. I was unsure about exposing my credentials. I hope I can get some help with the images, but if necessary I can try to send the stream. However, I need guidance on how I can put my flow here without exposing the credentials.

PS: I’m Brazilian. Sorry for the writing errors!

Thank you so much!



Hey @rfdepauli,

That normally happens when a value is empty, in the lookup you are setting a node by name. Does that node have 2 outputs or is it the same data as the incoming items to the Google Sheets node?

Thanks @Jon , but I already managed to resolve the error. I was looking for string-type information from a number-type data in the Google Sheets spreadsheet. I solved the problem by changing the way I looked for information in the spreadsheet! Thank you very much!

Hey, mate! Can you share more about the way you changed it? I’m having the same issue and the value aint empty :~
(I’m Brazilian as well, if you prefer to write in PT-BR I can translate later for other users :wink:

Hello Debora, how are you?! In my case the problem was that I was looking for information of type String in the IF node, but the information obtained in the previous node of the Google Sheets Lookup was of type number. I changed


it to type number and it worked!

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