GPT Model error - Won't connect to it's server

When I am using my GPT Model and look to call in another GPT Model, OS It it won’t connect to it’s server. System encountered a ClientResponseError when attempting to use the external API endpoint for fetching detailed data related to MOF technology applications in biomedical fields.

However, the model in question OS It does work in my models chat but only at the very start when there is no context built up. Once there is context from my model the ClientResponseError starts occurring.

it was working around 5 days ago: