If you open enough different LTI 1.3 assignments, your request size will exceed apache's limit

[cmcfadden]

When launching an LTI 1.3 assignment from Canvas, a state cookie is set during the LTI launch process.

Each state cookie adds a few hundred bytes to the request header.

Apache has a max request size of 8192bytes. So after enough launches, you'll exceed that and get an apache error.

Fix options:

• Flush the LTI state cookie explicitly after launch. Need to double check that there wouldn't be a case for needing that when, for example, running the LTI in an iframe and refreshing the browser.
• Up the size in apache to something larger

For an overview of apache's logic and how to raise the limit, see this article.