Commit Changes Error -- Unable to perform operation

**Describe the bug**
We are just in the process of getting set up with DevOps Center. We have managed to get as far as setting up a project with pipeline and we have a work item created. The work item has created the branch successfully in GitHub, so it appears as if things are connected correctly. If we make a change in the development org, the change is recognized in DevOps Center. So far, so good. The issue arises when we attempt to commit that change. The page shows that the commit was initiated and then it errors out and goes no further. It doesn't mention connecting with GitHub, so we're not sure whether the issue is with contacting GitHub or if it's on the Salesforce side before reaching out to GitHub. But, as we mentioned, the work item did successfully create the branch, so it appears as if Salesforce is speaking to GitHub properly.
If we scour the debug logs the only thing that stands out is that at some point Salesforce tries to hit a named credential endpoint that results in a 404 -- not found. The named credential is the DevOpsCenter Service. We're not sure if that has something to do with it or not.

**Expected behavior**
We are expecting that our changes be committed successfully so that we can then continue with the deployment process.

**Screenshots**

**Additional context**
We've gone through many setup guides and we think everything is set up properly in terms of the connected app, permissions, pipeline orgs etc.