teraßyte

Can you double-check the forums he's allowed to moderate? Maybe the one the topic is in is not in the chosen list. Or is he allowed to moderate all forums?

IPS can't help with 3rd party applications issues, and without knowing the application code or why it errors there really isn't much that can be done like this.
 
Since you can't get in contact with the developer, your best next option would be to hire someone from the providers list to investigate and fix the issue for you: https://invisioncommunity.com/third-party/providers/
I'm on that list too (link also in my signature) if you're interested. 🙂

No, there's no specific setting to disable it. You can either edit it out of the template or have a plugin made to disable it. Going the plugin way will keep your templates unedited and any future updates to it will automatically apply, which is what I usually suggest.
 
If you want to edit the template thought just find this code in "forums > front > forums > topicRow" (line ~113):
<a href='{$row->url( "getPrefComment" )}' class='' title='{{if $row->mapped('title')}}{$row->mapped('title')}{{else}}{lang="content_deleted"}{{endif}} {{if $row->canEdit()}}{lang="click_hold_edit"}{{endif}}' {{if $row->tableHoverUrl and $row->canView()}} data-ipsHover data-ipsHover-target='{$row->url()->setQueryString('preview', 1)}' data-ipsHover-timeout='1.5'{{endif}}{{if $row->canEdit()}} data-role="editableTitle"{{endif}}> and replace it with (basically remove the data-ipsHover attributes):
<a href='{$row->url( "getPrefComment" )}' class='' title='{{if $row->mapped('title')}}{$row->mapped('title')}{{else}}{lang="content_deleted"}{{endif}} {{if $row->canEdit()}}{lang="click_hold_edit"}{{endif}}' {{if $row->canEdit()}} data-role="editableTitle"{{endif}}>  

First let me remind you to take a backup of the core_members table before running these queries just to be safe.
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The column you need to edit is a bitoption one so you can't just use a straight field=value query.
 
You can use these queries but, as @Marc Stridgen already mentioned, you'd switch it off even for new members who never accepted them in the first place:
# Reset privacy policy UPDATE core_members SET members_bitoptions2 = members_bitoptions2 & ~32; # Reset registration terms UPDATE core_members SET members_bitoptions2 = members_bitoptions2 & ~64;  
You can try limiting how many members you reset based on their join date (or last visit/activity) to limit it to older accounts (which are likely to have accepted them already):
# Reset privacy policy UPDATE core_members SET members_bitoptions2 = members_bitoptions2 & ~32 WHERE joined < XXX; # Reset registration terms UPDATE core_members SET members_bitoptions2 = members_bitoptions2 & ~64 WHERE joined < XXX; Just replace XXX with the timestamp/date you want. Or use last_visit, last_activity or any other fields you might want to check.

Do you have the Radical Tags application installed perhaps?
 

When you move topics and leave a link this is the text the option has:
 
If you want to delete it right away simply select the link in forum view and delete it. Doing so will delete only the link in the old forum. The topic in the new forum will be left untouched.

That's not possible. You need an application (or a plugin) for that kind of functionality. I don't remember seeing anything like that in the marketplace though so you'll need one coded for you.

Confused. Do you want a list of topics or members with that code? Because it currently loads multiple topics and joins the members table. If there are multiple topics by the same user you end up with the duplicates in your screenshot.
 
If you want topics you should use:
foreach ($sql as $row) { $topics[] = \IPS\forums\Topic::constructFromData($row); }  
If, instead, you indeed want a list of users then you should check the user hasn't been added to the array already:
foreach ($sql as $row) { if (!isset($users[ $row['member_id'] ]) ) { $users[ $row['member_id'] ] = \IPS\Member::constructFromData($row); } } Or change the query that loads the data.

Asking everyone to clear their cookies often turns out to be a problem. A way to bypass this step would be to change the COOKIE_PREFIX constant too. That way old cookies (with the wrong domain set) won't be checked anymore. 😉
 
(Everyone would have to login again though.)

You have a lot of JS errors on the page when I look at the browser's console. That is causing the menu (and everything else JS-related) to not work. In your ACP go to "System > Support> Clear System Caches" and see if that works.

The problem here is that actually the addHeader() function doesn't have a 4th parameter to pass the ID. The ID is hardcoded to use the form id together with the header string and the name you provide as the 1st parameter instead:
public function addHeader( $lang, $after=NULL, $tab=NULL ) { /* Place the input into the correct position */ $this->_insert( \IPS\Theme::i()->getTemplate( 'forms', 'core' )->header( $lang, "{$this->id}_header_{$lang}" ), NULL, $tab, $after ); }  
So yeah, not exactly a bug. It would be nice it IPS allows to pass a custom ID as 4th parameter just like the other form helpers though.

Yes. The delete function uses that method in the last line for the IndexNow service:
\IPS\core\IndexNow::addUrlToQueue( $this->url() );