Short answer: your organization has no working Katapult credential stored. The message does not say so, and retrying will not help.
Why the message is unhelpful
It talks about loading jobs, so it reads like a Cloneable problem or a temporary glitch. It mentions neither Katapult nor credentials.
It also offers to retry, which cannot work: there is nothing intermittent happening. The same thing will fail the same way every time until the credential is in place.
So if you have pressed retry a few times, that was a reasonable thing to try and it was never going to fix it.
The fix
Someone with administrator access needs to do this.
Open your settings and go to Secrets Vault.
Look at the Platform Secrets tab. It lists each stored credential by name. The one Cloneable needs for Katapult is called KATAPULT_API_KEY, so either that name is in the list or it is not.
If it is not there, add it. Choose Create Secrets, then Add Platform Secrets, then pick Katapult. Cloneable fills in the name of the credential it needs and you supply the value.
Save.
Full detail in Store the credentials your integrations need.
Then try creating the job again.
If a Katapult credential is already there
The likely reason is that it no longer works. Katapult rotates or revokes keys, or they expire. If it was working and stopped, generate a fresh one in Katapult and replace the value here.
Worth doing in advance
This is the kind of thing that surfaces at the worst moment, usually when somebody tries to get a crew out. Storing the credential during setup rather than at the point of use costs nothing and avoids the whole situation. See Store the credentials your integrations need for when this needs to be in place.