Problem Connecting to business central

i have a power bi report published to the service that's been working for a long time. all of the suddent last friday, the refreshes started becoming very slow, to the point where sometimes the refresh times out (it is on a pro workspace, so it times out after 2 hours) up until yesterday, the refreshes would always time out until power bi turned off scheduled refresh due to consecutive time outs. 
i downloaded the file and opened power query, it was extremely slow, for a couple of tables, to a point where it is almost infinite and i would just end up getting an error message:

Failed to save modifications to the server. Error returned: 'OLE DB or ODBC error: [DataSource.Error] Dynamics365BusinessCentral: Request failed: The remote server returned an error: (429). (User Throttler: Too many requests reached. Maximum value is set to 5 concurrent requests and 95 requests waiting in the queue. Current number of concurrent requests: 5 and request queue size: 100. CorrelationId: bf09f780-d7a2-4ca9-982d-37fcb4ed1112.). '.

note that any other business central apis are working fine, except for this specific api.
what could be the problem?