TYPO3 前端错误：#1476045117 和 TYPO3 前端错误：#1580056272

Question

I am setting up a new TYPO3 Project for my company, this project is based on a previously existing Project, as the customer asked us to take it over. So I started with my company's kickstarter to create an empty but working Project. I then started adding the "old" content as well as the extensions used. Here I came across a problem: I added the news extension by Georg Ringer via composer and the frontend of the website showed the following Error:

(1/1) #1476045117 TYPO3\CMS\Extbase\Persistence\Generic\Exception\InvalidClassException
Could not find class definition for name "GeorgRinger\News\Domain\Model\DateTime
This could be caused by a mis-spelling of the class name in the class definition.

I found nothing about this online, checked my entire \ext-folder and didn't find anything related to this. I un- and reinstalled the news extension via composer but that didn't solve the problem either. I also have an issue, where I can't use the backend or the command line to flush my caches, so naturally I deleted the var\cache-folder and upon reloading my frontend I was prompted with another Error:

(1/1) #1580056272 TYPO3\CMS\Extbase\Persistence\Generic\Mapper\Exception\NonExistentPropertyException
The type of property GeorgRinger\News\Domain\Model\NewsDefault::eventStart could not be identified, as property eventStart is unknown to the TYPO3\CMS\Extbase\Reflection\ClassSchema instance of class GeorgRinger\News\Domain\Model\NewsDefault. Please make sure said property exists and that you cleared all caches to trigger a new build of said TYPO3\CMS\Extbase\Reflection\ClassSchema instance

I can still access the install tool as well as the backend. Clearing the cache doesn't change anything and my colleagues advised me to ask the TYPO3 community. This Project runs on TYPO3 version 10.4.12. Any and all help is appreciated, thank you. I am still very new to TYPO3, so please bare with me.

Answer 1

It turns out that there were two rogue DateTime 's hiding in one of the non-composer extensions that were missing the \ before them. I also had to add to my ext_emconf.php the following:

'suggests' => [
 'news' => '7.3.0-0.0.0',
],

Which also fixed the issue of me not being able to clear my cache, and upon reloading my frontend I saw content again. Thank you everyone on here and Slack for the help!