I am using version 3.2.2 of phpbb.
As an error occurs as shown below, the board can not connect itself.
SQL ERROR [ mysqli ]
Not unique talbe/alias: 't' 
And SQL error occurred while fetching this page. Please contact the Board Administrator if this problem persists.
This symptom occurred after the enable prefixed solved extension.
If prefixed solved extension is disabled, phpbb can be used normally.
Is there any way to avoid an error using the prefix solution?
I'm using these extensions.
I wonder what kind of extension are topic solved extension currently used by phpbb.com community.