Hi @IBN ,
Does this issue only occurs to the particular user?
How does the user creates the requests? Directly from the chat/channel or from the Approvals app in Teams?
As from the error message, seems like it's an issue of exceeding the requests limit, so in order to help narrow down the issue, personally I'd suggest checking if it's possible to cancel some requests in progress, then try again to see whether the user can create new approval request.
Besides, considering that Approvals in Teams is built on top of Power Platform, I'd recommend also trying to post in the dedicated community for PowerAutomate so that the community members there can help look into your issue as well.