My money is this: you disabled indexes to import your backup and you didn't re-enable them.
I would disable all of the extensions then re-enable them one by one to see whether a single one of them causes the cache to take an abnormally long time to rebuild.
Go to your admin control panel, in the Post Settings section, check out the Maximum image width per post and Maximum image height per post settings, make sure they're both set to 0. That check is costly and you're probably on a cheap host.
You're welcome, feel free to keep asking for unrealistic things and complain when people waste their time helping you.
Topic: BBcodes, possible to "or" stuff ?
Re: BBcodes, possible to "or" stuff ?
It's technically possible but I don't recommend it because it's too complicated for most users.
Start a new install on PHP 7.1 and the installer will tell you what extensions you're missing from PHP 7.1. ext/dom is the one from your logs but there are probably others as well. Do that before doing anything else.
It's related to phpBB but the first post doesn't mention any kind of pay or reward.
Fair enough. It's difficult to admit being wrong so I appreciate your response.