I have encountered difficulties in sending messages via the API. Specifically, I am receiving the following error message:

Error Response: {"error":{"message":"(#135000) Generic user error","type":"OAuthException","code":135000,"error_data":{"messaging_product":"whatsapp","details":"Generic user error"},"fbtrace_id":"A1waaM6nHFNACvy0TmQySEo"}}

I have thoroughly reviewed our integration setup and confirmed that all parameters are correctly formatted and that our access token is valid. Additionally, we are adhering to WhatsApp's template policy, and our custom templates have been approved.

It's worth noting that we were able to successfully send messages using the default template (Hello_world) yesterday. However, for the past 2 days we are unable to send any messages other than the default template and we are facing the "Generic user error".

Given the urgency of our situation and the impact on our operations, we would greatly appreciate any assistance or guidance to resolve this issue promptly.