In password security, the longer the better. With a password manager, using more than 24 characters is simple. Unless, of course, the secure password is not accepted due to its length. (In this case, through STOVE.)
Possibly indicating cleartext storage of a limited field (which is an absolute no-go), or suboptimal or lacking security practices.
There’s a site I use that does that on the password reset page, but not when logging in. So when using a long password it’s as if the reset never works. Took me ages to figure out what was going wrong.