Upgrade to Version 3.2.7 = Cannot connect to database, access denied. Please check your configuration

Please do not refer me to old/irrelevant posts, all those “fixes” date back to 2015 and have no bearing. Those posts also appear to remain open (unsolved) although no such documentation as “resolved” is posted,.
Here’s the problem: I had it up and running last fall, perfectly.
Today I need to use pHpList, results: "Cannot connect to database, access denied. Please check your configuration or contact the administrator."
No changed made since it was running perfectly, except the winter weather.
Older similar posts: I have run every “fix” but no solution.
The dB name, dB user & username, and dB PW are correct.
What has happened to pHpList, is it dying?
mit freundlichen grüßen/best regards,
p.s. I first noticed getting this error a few days ago, when I received an email suggesting the “security upgrade” to version 3.2.7. Now I wonder, has pHpList died and gone to hell?

Hopefully you saved your config.php file from the previous version.
If the software is complaining that it cannot connect to the database, something is wrong with either the database host, username, or password.

If you can put your old config.php in place of the new one (rename the new one, don’t delete it), you should at least be able to get the database connected, then go from there