已解决！我希望这会在将来对其他人有所帮助.即使我启用了gmail"访问较不安全的应用程序"，它仍然拒绝了PHPmailer登录. ，至少对我来说如此，所以我将其切换为465，一切开始正常进行.

Resolved! I hope this helps others in the future.. Even though I enabled gmail "access to less secure apps" it kept rejecting the PHPmailer sign in.. Seems that for some reason gmail wasn't accepting port 587, at least for me, so I switched it to 465 and everything started working right a way.

作为此答案的一个加分，至于@Amit Merchant在评论部分中建议的内容，我不知道***.com/a/33667250/1485183中的最后一条评论是什么，它基本上显示了gmail功能寻找问题的解决方案时，我从未发现或听到以下消息:accounts.google.com/DisplayUnlockCaptcha

As a plus for this answer, as for what @Amit Merchant suggested in the comment section, I wasn't aware of what the last comment in ***.com/a/33667250/1485183 says, it basically shows a gmail feature I never found or heard when looking for a solution for my problem, that this: accounts.google.com/DisplayUnlockCaptcha

我确定，不管是用于phpmailer还是任何其他库，这有一天都会对某人有所帮助.

I'm sure this will help someone some day whether if it's for phpmailer or any other library.