Your existing services in the JLS Middleware project are deploying successfully from GitHub, so the account-level GitHub connection is working. Could you share which specific repo is not appearing in the picker, and whether you see some repos but not that one, or no repos at all? A screenshot of what the repo picker shows would also help us pinpoint the issue.

https://github.com/lpj-jls/zendesk-linnworks-product-sync/ is the repo I am trying to connect

I see my login to Railway is using lpjweb github username, but the github integration is using lpj-jls username - could they be causing issues between each other?

Your existing services are deploying from repos under lpj-jls, so the GitHub App installation on that account is working for those repos. The mismatch between your Railway login (lpjweb) and the GitHub App account (lpj-jls) isn't blocking things on its own. Since lpj-jls/zendesk-linnworks-product-sync is under the same account as repos that do appear, the most likely cause is that the GitHub App's repository access doesn't include that specific repo. Go to your GitHub App installations, click "Configure" on the Railway app for lpj-jls, and confirm that the repo is listed under the granted repositories, or that "All repositories" is genuinely selected there.