Cookie information for WiscWeb website owners

A recent Tech Partners thread brought new attention to the ongoing conversation about cookie concerns on campus. This is something we’ve been addressing and communicating about for the past year, and we’re happy to see people engaging with the topic. Here is everything we know in a single post to make things easier for users to reference.

What is a cookie?

Cookies are small text files that store pieces of data when you visit a website. You may have noticed that many sites now require you to consent to cookie tracking. This is because a lot of tools are using cookies for harvesting data. It’s not necessarily a bad thing. It’s just something that is more common now.

What is happening?

When visiting WiscWeb sites or any web service that uses a subdomain of, you may have encountered an error that says something about “Too many cookies.” This has been an ongoing issue since early 2023 (possibly even fall of 2022). We think this could have been impacted by the change from Universal Analytics to Google Analytics 4, but are not certain.

MyUW, the KnowledgeBase, and some UW Extension websites have also experienced the issue, and likely more services on campus that have gone unreported. This issue is bigger than WiscWeb.

Here’s what we know:

  • Web tracking tools like Google Analytics, Google Tag Manager, and Hotjar set cookies when you navigate to various campus websites.
  • A lot of these tracking cookies are automatically set to the top-level domain. Therefore, when users visit any subdomain of (like your sites!) these cookies keep adding up.
  • Tracking tools often set the cookie for 1-2 years, so the timeline for a user to accumulate a ton of cookies is VERY long. Over time, the size of the cookies become too big for the server to handle, causing a broken page or an error screen.
  • In order to view the webpage, users must clear their browser cache and cookies, which removes the accumulated cookies.
  • Most servers have a request limit of 8,000 bytes. If a request comes in with more than the allowed size, the server rejects the request. Cookies contribute to this limit.

What have we done to help?

If you’re wondering if we’ve made any changes that help remediate this issue, the answer is a resounding yes! We’ve already done everything in our power to help limit the impact on our users. Here’s an overview of the changes we’ve made:

  • We updated the domain that Google Analytics cookies get set to in the UW Theme so that it does not use the top level domain. Instead, it uses the domain of the site with the Google Analytics tracking installed on it.
    • Unfortunately, we are unable to influence the cookies for Google Tag Manager. These must be set in the Google Tag Manager dashboard by the owner of the GTM account.
  • We updated our system to display a more helpful error, with links to documentation on how to clear cookies in various browsers.
    • Note: We can’t link to KnowledgeBase docs in the error. If you experience this issue, you will also be unable to visit the KB as it will also be impacted. Therefore, our error links to external vendor documentation.
      Error 431 indicates that you have too many cookies set in your browser.
  • We have compiled information about this issue and shared with various impacted groups across campus.
  • We have communicated the issue in several Lunch and Learn sessions.

What can you do to help?

  • Discontinue use of Hotjar – Hotjar is one of the biggest culprits for this issue as it sets the cookie at the top-level domain and doesn’t offer an option to change it. Hotjar cookies are also quite large, which is contributing to users hitting the cookie limit more quickly. We highly recommend discontinuing use of Hotjar entirely.
  • Specify a subdomain for tracking cookies – If you’re using a tracking service that sets cookies, check their documentation to see if it is possible set the domain for the site level. We’re already setting this correctly for Google Analytics within our service but other tools (like Google Tag Manager) may not be configured appropriately. If you are using Google Analytics through Google Tag Manager, you will need to correctly configure your settings (if you’re not sure, please reach out to us).
    • For groups that use Google Tag Manager to insert Google Analytics 4, please make sure to add a new configuration parameter for “cookie_domain” with the value of “none” to your Google Analytics 4 tag (Learn more about customizing cookies in GTM):

How to avoid this issue as a user

While it is the responsibility of website owners to implement cookies correctly, there are some steps you can take to avoid seeing these issues yourself:

  • Get an ad blocker – You could consider an ad blocker for your browser to block cookies from being set when you visit websites.
  • Clear cache and cookies – Most importantly, if you run into the error here on the screen, just clear your “All Time” browser cookies, close your browser window and restart. That’s the best way to clear out the cookies.
    • Note that some browsers will default to only clearing cookies for the past hour. You may have to manually update that to say “all time” or “all” cookies.


Please direct questions to our Customer Support Form. We’d love if you could read through the info above before sending in requests, to ensure you understand the basics. However, we understand this is a complicated issue that may merit more discussion with your group.