Troubleshooting: HTML5 – DemandScience Help Center

Below is a list of common HTML5 errors and how to solve them.

Invalid File Name

File names uploaded into DemandScience can only contain the following:

alphanumeric values
hyphen, underscore, period (hyphen and underscores can not be right before the file extensions)

Valid sample filenames:

file_name123.gif
example-file.mp4

Invalid sample file names:

File | name123.gif (spaces/pipe not allowed)
file-name_.jpg (underscore not allowed before the period)
.filename (filename cannot start with a period)
filename@123.gif(@ not allowed)
file(name)@123.gif(parenthesis not allowed)

ClickTag script not found

The Tradedesk requires a compatible clicktag to be installed on each creative submitted in order for it to be clickable. Instructions on how to add appropriate clicktags are available in each html5 guide.

No valid ad dimensions found in 'ad.size' meta tag

To pass validation on the DemandScience platform, each creative will need a meta tag that declares the creatives dimensions. The meta tag format can also be found in the guides above

<meta name="ad.size" content="width=W,height=H">

Its placement can vary based on the program used to create html5 but it will typically be placed with other meta tags.

Some tools will automatically install a dimensions meta tag in each creative. Some tools may require the meta tag be placed and the values entered manually.

No html files present at root level

When zipping html5 creatives together, the html file can't be placed within another file or zipped by itself. This will cause the error to appear.

The following instructions are available in each of the html5 guides - "Zip the .html , .js and images folder together, DO NOT zip the files as a folder underneath a folder, the .html needs to be on the root level of the zip directory. "

Failed to copy asset

This error will appear if there are any extra spaces or characters in the Ad Size Meta Tag.

Please ensure the meta tag is added exactly as mentioned in each HTML5 article.
<meta name="ad.size" content="width=W,height=H">

Example - <meta name="ad.size" content="width=160,height=600">
Examples that will cause an error- adding a space before the word height, adding any other characters:

Creative validation failed - DSP requirements not met

MACOSX & .DS_Store

This error is saying that within the folder, there is a file that contains MACOSX and/or .DS_Store. Neither of these files are able to be uploaded and must be removed from the folder.

The MACOSX files are created when a Mac user creates and archives (zips) files using a Mac. If this Mac user then sends the zip file to another Mac user, the folder will remain as a hidden folder. When a Mac user sends this file to a PC user, they are able to see the file and vice versa for the .DS_Store files.

If you download an app like ForkLift, it will show hidden folders in zipped files. Also, a third party zipping/archiving app like Keka will have the option to exclude the Mac resource forks which include files like _MACOSX & .DS_Store. This will allow you to upload the files without an error.

You can also zip files without the _MACOSX file using the zip command in the Mac Terminal - please see steps on this process at the below link -
https://apple.stackexchange.com/questions/239578/compress-without-ds-store-and-macosx

Screenshot 2025-03-26 at 1.41.17 PM.png