REST execution time exceeded error

I executed a POST of the Attachment API at 2:00 on 12/26 using curl.
After the Attachment API is called, the process is to add the CSV to the sys_attachment table and Business Rule adds the CSV data to the u_budget table as a record.
The trigger for the Business Rule is set to "when a CSV with a specific file name is inserted into sys_attachment".
The other day, a CSV containing 8000 data was linked, but only 2800 records were added, and the following REST execution time exceeded error was output to the log.

Exception while executing request: Transaction cancelled: maximum execution time exceeded: com.glide.rest.util.RESTRuntimeException: Exception while executing request: Transaction cancelled: maximum execution time exceeded: 	com.glide.rest.handler.impl.ServiceHandlerImpl.handleInvocationTargetException(ServiceHandlerImpl.java:76)

Why is this error being output?
What is the solution?