Jenkins unable to get ssh-agent to work, looks for a missing askpass_*.sh file

I installed the ssh-agent before and had everything working nicely with an ssh key that has all the proper permissions for cloning repos from a github project, but now after setting up another instance of Jenkins (as closely as I could, I didn’t clone it when I should have), I get the following error:

$ ssh-agent SSH_AUTH_SOCK=/tmp/ssh-4CemQOSbNiXl/agent.4477 SSH_AGENT_PID=4479

Running ssh-add (command line suppressed)

ssh_askpass: exec(/home/ubuntu/.jenkins-slave/workspace/ippy_feature_jenkins-builds-FOF44763DY7BL4HHQ5XQK5MYECXWHFCEFWC4PHU6FWHKBZV6RNSA@tmp/ No such file or directory

This is being used with the sshagent (credentials: ['correct-key-here']) in the Jenkinsfile in the repo.

Thanks for any info