@flippy2810
You may have a conflict with your Theme or another Plugin.
Read this guide about “How to do a plugin/theme conflict test?”
OK, now I know what the problem is.
The reCAPTCHA plugin was to blame. Enable for Login was enabled in the reCAPTCHA status settings.
Enable for Login —-> Applies to Standard Login, WooCommerce & Easy Digital Downloads logins
If this function is deactivated, the login works.
@flippy2810
You can use the free UM reCAPTCHA Plugin