Activity Monitor paused. The wait operation timed out

Hi MuneebAshraf --

This error usually indicates that SQL Server is very busy and/or has insufficient resources available to execute the queries used by Activity Monitor.  I would recommend checking SQL manually using a query such as "sp_who2" to see what is actively running.  You may also want to look at Task Manager or Resource Monitor on the server itself.  I've also included a query below that you can execute in SQL Server to get an understanding of CPU utilization.  Take care.

	   DECLARE @ts_now BIGINT
		select @ts_now = cpu_ticks / (cpu_ticks/ms_ticks) from sys.dm_os_sys_info; 
        
        SELECT record_id,
                DATEADD(ms, -1 * (@ts_now - [timestamp]), GETDATE()) AS EventTime, 
                SQLProcessUtilization,
                SystemIdle,
                100 - SystemIdle - SQLProcessUtilization AS OtherProcessUtilization
                --CAST(record AS XML)
        FROM (
                SELECT 
                        record.value('(./Record/@id)[1]', 'bigint') AS record_id,
                        record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'bigint') AS SystemIdle,
                        record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 'bigint') AS SQLProcessUtilization,
                        TIMESTAMP
                FROM (
                        SELECT TIMESTAMP, CONVERT(XML, record) AS record 
                        FROM sys.dm_os_ring_buffers 
                        WHERE ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR'
                        AND record LIKE '% %') AS x
                ) AS y 
        ORDER BY record_id DESC