Threads (child) not showing up in General (parent) section. Timeout issue? Size?

[iunlock]

I'm having a similar / related issue:

Here is the issue:

GENERAL (Main)
-> General Discussions (Parent)
-->Tread 1 (child...)
-->Tread 2
-->Tread 3
-->Tread 4
-->Tread 5

Thread 1 is pretty big in size. Almost 10,000 posts.

All the Threads 1 through 5 do not show up, while all the other threads in the other sections of the forum are just fine.

Theory:

Could it be that Thread 1 is so big that it's timing out before it gets a chance to load all the threads in that section? Does the default value of whatever it is need to be changed to a higher limit?

Note:

I can only access Thread 1, by clicking on an icon (paper shaped) to the left of the "General Discussions." Also, everything seems to be fine when using the Android App, TapaTalk. It just can't be seen when using a browser.

Here are the errors when trying to post a thread using the computer browser:

Connection Problems
Sorry, SMF was unable to connect to the database. This may be caused by the server being busy. Please try again later.
Warning: Cannot modify header information - headers already sent by (output started at /home/hostname/public_html/mywebsite.com/Sources/Errors.php:415) in /home/hostname/public_html/mywebsite.com/Sources/Errors.php on line 346

...and it repeats the Warning message part six times with these lines: 346, 347, 348, and 351, 352, 353.


Here are those lines in Errors.php:

Line 346: header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
Line 347: header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
Line 348: header('Cache-Control: no-cache');

Line 351: header('HTTP/1.1 503 Service Temporarily Unavailable');
Line 352: header('Status: 503 Service Temporarily Unavailable');
Line 353: header('Retry-After: 3600');

...

Before I change anything, I would like to seek some advice first.

Thanks in advance.

[Illori]

topic split so that you can get your support and not confuse people with 2 issues in one topic.

[Jade Elizabeth]

Do these errors only happen when you are loading that board? Do they happen on the default theme too?

Also are you on shared hosting? The biggest SMF forum known has 17k posts in one of their topics and they are not having issues.