White screen on just a few posts 2.0.15

[bfeist]

Hi all,
I'm a happy user of SMF. I've been using it for many years to run a local hobby group forum and it has always been amazing.

I'm hoping someone can help with a problem that has just cropped up. one or two forum topics result in a white screen. All others work perfectly. I've searched this forum and done some googling and have turned on PHP error reporting and searched every PHP error log and I can not see an error being thrown anywhere. PHP version is 5.6.33. Viewing source on the blank screen shows no markup whatsoever. It's a real mystery. I'm a dev by trade, but I can't find a way in to problem solve this without being able to see an error anywhere. Can anyone recommend a way in?

Thanks in advance.

[Sir Osis of Liver]

Link to a blank topic?

[bfeist]

http://temac.ca/smf/index.php/topic,6439.0.html

[Illori]

try installing https://custom.simplemachines.org/mods/index.php?mod=4111 and see if it helps.

[lurkalot]

Is there something strange going on with your url's

The link you posted, http://temac.ca/smf/index.php/topic,6439.0.html

This works, http://temac.ca/smf/index.php?topic=6439.0

Edit:  Sorry my mistake, it doesn't

[Illori]

the second link does not load the topic, it loads the board index. so they are not the same.

[Sir Osis of Liver]

That's odd, something's changing the urls.  This one works -

http://temac.ca/smf/index.php/topic,6297.0.html

Something in .htaccess?

[bfeist]

try installing https://custom.simplemachines.org/mods/index.php?mod=4111 and see if it helps.

That did the trick. Thanks so much!

[Sir Osis of Liver]

Why would that affect urls?

[Illori]

the topic must have had attachments that were hitting the memory limit and causing a white screen.

[Sir Osis of Liver]

Why would that affect urls?

[Illori]

it does not affect the URL, it affects the page that the post with the attachment on it is on.

[Sir Osis of Liver]

I understand that, but why are the urls changed to .html links?

[Arantor]

Because the 'search engine friendly URLs' option is turned on. It's a core feature since, well, pretty much forever when in the olden days search engines would assume everything with a ? in the URL was automatically duplicate content.

[Sir Osis of Liver]

Hmm, I must have a different server setup, that option has no affect on my installs.

[Arantor]

It also only works in Apache.

[Sir Osis of Liver]

Support and Credits reports server running LiteSpeed, my account info shows Apache 2.4.9.

[bfeist]

For the record, the images that caused this error were only about 600k, but they were very high resolution 5500x3000