what is the Maximum Number of replica download possible from download.geofabrik.de?

I am trying to update more than 5 months of Nominatim europe data from download.geofabrik.de. For 8 to 10 days its works fine but after that it showing error failed to open stream: HTTP request failed! HTTP/1.1 500 Internal Server Error

Is there any restriction in downloading replication from download.geofabrik.de server per IP?