[General] Any Plugin not work on my forum

[omorsharif]

Hello Respected MyBB.

At first i used mybb 1.8.3, last month i changed server, then any plugin not work in my forum, plugin show correctly in plugins section, i install and activate plugin and plugins activated but not work, i try many plugins like- my advertisement, latest post on sidebar etc.
i already upgraded mybb 1.8.6 version but same problem here.
i do not understand where is my fault...............
my site url- we-freelancer.com

[.m.]

have you run file verification tool (available at tools & maintenance section) ?

[omorsharif]

yes sir i already did this.
and...show this
File Verification: Found Problems
inc/db_mysqli.php Changed
inc/db_mysql.php Changed

i modified these files yesterday, because after upgrade to 1.8.6, site acp had very slow and i did not perform backup, so i search this forum and found a post about this modification.
but my problem begun after server changed.

[.m.]

^ if direct help required, assuming that you have a legit forum (see support eligibility policy)
you may PM me temporary access to forum admin panel & files (FTP) to check it

[omorsharif]

sent sir