Can not Add NEW PRO site LEVELS? Please help

Hello there

I am not able to add pro sites LEVEL.

Please help

the boxes where we type the name of pro site LEVEL, price for 1 month, 3 months, 12 months is not there now.

I already have 3 pro site LEVELS, now i am trying to add the 4th Level. But something is not going good there

this is the url path where i am getting the error : /wp-admin/network/admin.php?page=psts-levels

I am using the latest version of wordpress

Thanks in advance!