Not Acceptable! An appropriate representation of the requested resource could not be

I have following link 

Code:

<a href="<?=base_url()?>controller/controller_method/<?=$l1."/".$l2?>">

where 

Code:

$l2

 contains Abhishek Amit but when i click on this link instead of getting on next page i get following error message Not Acceptable!

An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security. I have tried using url_encode() but that is also not working. This issue is only on server (shared hosting) it is working properly on wamp server. Please give solution to the above issue

<a href="<?=base_url()?>controller/controller_method/<?=$l1."/".$l2?>"> will output? What is $l1 value? Maybe you URL character is disallowed by codeigniter.

Keep calm.

<a href="<?=base_url()?>controller/controller_method/<?=$l1."/".$l2?>"> will output? What is $l1 value? Maybe you URL character is disallowed by codeigniter.

$l1 contains id i.e. 2 and $l2 contains name with space between them i have checked disallowed character but it is not working. Please give any suggestion.

And you say your value of L2 is 'Abhishek Amit' but spaces are not allowed in urls. Even if it gets replaced with &nbsp; or %20% these are all prone to cause problems.