If there are more than 1,000 rows in the routing table on a Mikrotik router, the table won´t be retrieved via API since it is very likely it contains all dynamic routes which means a long time for its processing leading to the failure of the script for time out.
The reason for this is that ISPadmin must be able to work with less capable routers, too. Retrieving the routes is not critical for the functionality, whereas router update is performed.