It is very difficult to diagnose with limited info, but what you’ve done is correct, ie: save config.php and then restore after uploading.
Thanks @llljackll for the pointer to the system page, that was last updated in October 2017 and something is nagging me about PHP versions, but as you say, that page says 5.4.5 should be okay, though PHP themselves recommending updating where possible for security reasons.
Normally, a blank page is the result of a missing quote, single or double, and semi-colon in the config or any language file you’ve altered. But, without seeing the issue for yourself, it is very difficult to answer. One thing you could try is to re-upload the 3.3.3 lists folder and make sure that all files went over.
You have a backup in case as you’ve already stated.
Genius! I have been scratching my head over this for a few days. I’ll ask my hosting company to upgrade the PHP version but deleting the plugin did the trick.
I’ll try editing the plugin and re-instate it & see if it works - I’ll keep everyone posted.
Thank you everyone for your suggestions to a irst time poster!
Just for anyone else banging their head against the wall with this issue, I can confirm that, in this particular instance, deleting the Segment plugin does the trick. Saves me a lot of debugging. I’m so glad I persisted searching for a solution when I was just about to give up, rather than trying to fix it myself. Thank you so much!