I think I should think of giving up

[frank18]

There may be a myriad of reasons why the error "mysql has gone away" appears. See https://dev.mysql.com/doc/refman/5.0/en/gone-away.html

[adb34]

The thing is I cannot get FEC to work in checkout as well. No matter what I do, it will not work. I have posted on that thread and all suggestions also do not work.

[kobra]

The thing is I cannot get FEC to work

Really need to know all of the plugins you have loaded

[adb34]

Really need to know all of the plugins you have loaded

I listed the plugin, on the FEC thread

[mc12345678]

The thing is I cannot get FEC to work in checkout as well. No matter what I do, it will not work. I have posted on that thread and all suggestions also do not work.

I took a lap through the discussion in the FEC forum and 1) would suggest continuing to troubleshoot FEC through that thread, 2) would suggest settingup a temp store, and install just FEC to verify functionality in your test environment, 3) would suggest that you slow down... There have been a few threads where you've had difficulty installing a plugin, to then state that it has been removed to find out that only this part or another was removed not the entire plugin. Now in FEC you've stated that you've removed all code from the orders.php file except the FEC part, well this could cause new errors to be generated. The more things are affected at once, the harder it is to figure out what the problem is. Effectively need to change one thing at a time. This is not to say that a single line in a file be changed, but complete an installation, complete a removal, etc... before testing the current status or checking functionality. Also while writing this I see kobra has posted about needing to know which plugins are installed. This is why when posting about an issue it is recommended to address the items in the posting tips.

[kobra]

I listed the plugin, on the FEC thread

I looked back to your post dtd 23 Aug 2015, 09:43 AM and forward from there and did not see where you listed ALL your plugins

[DrByte]

Perhaps mysqli_* is a little more aggressive with dead / idle link cleanup?

It's very possible that hosts haven't tuned their defaults as well as they had with the older mysql stuff. Or the defaults are just stricter and need tweaking where tweaking wasn't needed before. The tweaks could be to both the php.ini (for PHP server side) and the my.cnf (for MySQL server side)

[lloyd_borrett]

Any idea as to what those tweaks might be Dr Byte?

[DrByte]

PHP Warning: mysqli_query(): MySQL server has gone away

It's very possible that hosts haven't tuned their defaults as well as they had with the older mysql stuff. Or the defaults are just stricter and need tweaking where tweaking wasn't needed before. The tweaks could be to both the php.ini (for PHP server side) and the my.cnf (for MySQL server side)

Any idea as to what those tweaks might be Dr Byte?

Googling for the error message "MySQL server has gone away" brings up tons of articles suggesting various server-side tweaks:
http://stackoverflow.com/questions/1...large-sql-file
https://dev.mysql.com/doc/refman/5.0/en/gone-away.html
and lots more

Another possibility is that in your Zen Cart site you might have added custom code to prematurely call application_bottom.php or otherwise close the session and/or database connection, in which case simply "not" doing that would be advisable.
And of course using old versions of any ZC code files copied into a newer-version site can cause undesired effects.