HTLC routing issues in custom LN plugin (c-lightning) on regtest network

I am working on a custom routing plugin for CLN on a regtest network. My goal is to compare its performance against the classical rebalancing plugin provided by the CLN community.

Now I am trying to test it with zero fees routing. However, I am encountering issues with HTLC execution (even in a classical plugin, so I assume I have some problems in a setup), and payments are failing with various errors like "WIRE_FEE_INSUFFICIENT," "WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS," and "WIRE_TEMPORARY_CHANNEL_FAILURE." I have already set cltv-delta to 6, fee-base to 0, and htlc-minimum-msat to 0 in my nodes' configuration and ensured that nodes have sufficient liquidity in its channels for routing.

However, the errors persist. I suspect there might be other factors influencing the HTLC routing process or issues with my plugin's logic.

Can someone help me troubleshoot this problem and suggest potential reasons for these errors? Is there anything else I should be considering in my custom plugin to ensure smooth HTLC execution?

Thank you in advance!

Ok I move my comment to an answer

It is hard without taking a look at your code, but WIRE_FEE_INSUFFICIENT is a pretty clear error, there is no enough fee to route the payment.

WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS Are you building your payment in the wrong way? WIRE_TEMPORARY_CHANNEL_FAILURE The channel is not responsive or something happens. Take a look at your log, it should contain the workflow that your lightning node did before the error

In addition, core lightning was not good when there was a single channel between two nodes. Because the pay command will split the implementation in multiple ones.

However, in core lightning v23.08 this was improved as the release notes mention https://github.com/ElementsProject/lightning/releases/tag/v23.08

So I will retry with the new version too :)