Users unable to access threads other than their own
This error only occurs when the users are logged in
Please ask that user to click on "Mark all read" link located in forum foot. This will fix the problem.
Were is no any option for limiting characters count of a post title. you need to modify the wp-content/plugins/wpforo/wpf-includes/class-topics.php file.
Find the following line and decrease the second argument (250) as you like:
$args['title'] = wpforo_text($args['title'], 250, false);
We'll take into consideration to add a new option, that will allow controlling this limitation from Dashboard.
You can also hide the large titles on front-end using CSS text-overflow property.
More info here: https://www.w3schools.com/cssref/css3_pr_text-overflow.asp