Every time member logs in, the password does NOT work

I have a member who always has to request password reset for the club website. She claims she has never had issues until recently.
I had another member a year or more ago who lived with it.

Can you prevent this?

We will need more information,
Club number
Member first name
Operating system and version
Browser and version

Club number is 2854329
First name of member is NELLY
OS is MacOs High Sierra Version 10.13.4
Browser is Safari Version 11.1

This problem happened on May 3, May 17, and again June 2, 2018.

Previous emails I received as administrator from this member were on 2/28/16, 4/15/2016, 7/8/2016, 3/6/2017, 7/9/2017, and 8/5/2017. These emails are information only and request password reset.

Has her name / designation changed? e.g from Jenny Green to Jenny Green, CC, CL

It is possible that she has a "different" name / password in cache.

Ask her to enter her email address instead of her name, with her current password and see if that works. If it does she should try clearing her cache