Lexoffice error: Halted Exception: Unable to upload file: The file extension does not match the file type.

Lexoffice Zap does not upload invoices sent to a particular email address


I set up a lexoffice zap with Zapier yesterday. Basically, the zap has to do the following:

An invoice is sent to our email address called After the email arrives in the inbox, it should be uploaded to our bookkeeping software lexoffice.

Yesterday, this worked very well.

Unfortunately, as of today, it does not work any longer.
The IMAP by Zapier part works fine. I already checked it and got the confirmation by Zapier as well.

However, the lexoffice upload does not work as intended.
I always get the following notice:

This lexoffice step hit an error

Error message: Halted Exception: Unable to upload file: The file extension does not match the file type.

It should be noted that only .pdf, .jpg, .png files are permitted. All emails included pdf invoices.

Attached to this post, you will find an image that causes the error in my opinion. I think the file name and file are wronly set.

Does anyone have an idea why this zap does not work?

I appreciate your help and ideas regarding this zap.

Have a nice day.



5 replies

Userlevel 7
Badge +14

Hi @NiklasUS 

The field “Filename with Extension” expects a file name with extension, but you have a file object mapped.


Userlevel 7
Badge +14


Another thing to check is if there are multiple attachment(s), then those are probably getting put into a .ZIP file.


@Troy Tessalone Thank you for your answer. The emails include solely one single invoice pdf file. I only get a hydrate string so I do not know how to generate the filename with extension. I tried to run a python code to generate the filename with extension. Unfortunately, it did not work.

Do you have any ideas on how to fix this?

I thank you in advance for your help.

Userlevel 7
Badge +14


What about using the email subject line as the file name OR your own combo of static/dynamic values to create a file naming convention?

Insert a timestamp to make the file name unique:

Userlevel 7
Badge +11

Hi @NiklasUS 👋

How are things going on this? Were you since able to get the Zap generating unique filenames with the file extension included? 

Keen to ensure you’re all set so please let us know whether you’re still in need of any assistance on this - happy to help further! 🙂