BigIP F5 LTM fails during Load testing

All signs point to you are hitting the rate limit enforcer of the license.  

Are you seeing anything in the logs on it?

show /sys log ltm |grep -i 'bandwidth utilization

To run a load test you will need to use a system that would not be limited to to such a low value of network bandwidth. 

 Here is one from my lab

perf_VE_throughput_Mbps [25]
admin@(ip-10-0-1-11)(pid-25975)(cfg-sync Standalone)(Active)(/Common)(tmos)# 

 You may only have one TMM on the system (sorry I do not have the same license in my lab)

admin@(ip-10-0-1-11)(pid-25975)(cfg-sync Standalone)(Active)(/Common)(tmos)# show sys tmm-info | grep Sys::TMM
Sys::TMM: 0.0      
Sys::TMM: 0.1      
Sys::TMM: 0.2      
Sys::TMM: 0.3      
admin@(ip-10-0-1-11)(pid-25975)(cfg-sync Standalone)(Active)(/Common)(tmos)# 

Running the command  again without the grep would let you see which TMMs are being used during your tests

admin@(ip-10-0-1-11)(pid-26549)(cfg-sync Standalone)(Active)(/Common)(tmos)# show sys tmm-info

---------------------------
Sys::TMM: 0.0      
---------------------------
Global             
  TMM Process Id      18860
  Running TMM Id          0
  TMM Count               1
  CPU Id                  0
                   
Memory (bytes)     
  Total                5.1G
  Used               566.4M
                   
CPU Usage Ratio (%)
  Last 5 Seconds          1
  Last 1 Minute           1
  Last 5 Minutes          1

--------------------------
Sys::TMM: 0.1      
--------------------------
Global             
  TMM Process Id     18860
  Running TMM Id         1
  TMM Count              1
  CPU Id                 1
                   
Memory (bytes)     
  Total                  0
  Used                   0
                   
CPU Usage Ratio (%)
  Last 5 Seconds         1
  Last 1 Minute          1
  Last 5 Minutes         1

--------------------------
Sys::TMM: 0.2      
--------------------------
Global             
  TMM Process Id     18860
  Running TMM Id         2
  TMM Count              1
  CPU Id                 2
                   
Memory (bytes)     
  Total                  0
  Used                   0
                   
CPU Usage Ratio (%)
  Last 5 Seconds         1
  Last 1 Minute          1
  Last 5 Minutes         1

--------------------------
Sys::TMM: 0.3      
--------------------------
Global             
  TMM Process Id     18860
  Running TMM Id         3
  TMM Count              1
  CPU Id                 3
                   
Memory (bytes)     
  Total                  0
  Used                   0
                   
CPU Usage Ratio (%)
  Last 5 Seconds         1
  Last 1 Minute          1
  Last 5 Minutes         1

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