Hello Dynamicsuser365,
Kindly check in below areas if all setups are fine.
--- Go to System administration > Users > Users. Make sure that this user "Greg" has appropriate roles assigned to approve the payment journal.
--- Make sure that the user "Greg" is set to enabled in the "Users" form.
--- Make sure that the Person is assigned to this user in the "Users" form.
--- Also check if appropriate privilege is assigned to the user role to approve the payment journal. Below screen shot is taken from D365 for your understanding. Here the privilege is Approve vendor disbursement journal and Approve customer payment journal.

--- Also make sure that the user "Greg" has been granted the access to appropriate organization to approve the payment journal where it was created and submitted for approval. This legal entity specific grant you can set in the "Users" form itself.
Kindly check and update in this forum.
Best regards,
Sourav Dam
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