Random Network Dropouts [STP status Forwarding ]

I am facing network drops. Ports goes up and down and in logs I could see this behavior. All servers are effect which are connected to the switch. 

Could you please let me know how to solve this issue.

Info       	 %LINK-I-Up:  gi1/0/11    	
Warning    	 %LINK-W-Down:  gi1/0/11    	
Info       	 %LINK-I-Up:  gi1/0/11    	
Warning    	 %LINK-W-Down:  gi1/0/11    	
%STP-W-PORTSTATUS: gi1/0/6: STP status Forwarding    	
%LINK-I-Up:  gi1/0/6    	
Warning    	 %LINK-W-Down:  gi1/0/6