Hi I started working on a client's website as a content creator last week I was able to login just fine when they added me on Wednesday for the past few days however, all of a sudden, today when I tried to log in the wp -admin or the wp-login changed to not_found and when I tried to sign in via WordPress or the link that I was given when I first was added it says this user doesn't exist. I can't figure out what the issue is for the life of me. I am still there on their site as an admin apparently when I asked today but I can't access anything at all and I've been trying all day. There have been errors with the site over the past few days however, Other admins have been able to access the site without any issue its just me. I've cleared my cache and everything so what else can I do. I really need this answered because they are going to kick me off the project if I am unable to access the site. Thanks for the help

If you’re saying /wp-admin/ sends you to an error page while not logged in that means either an error in the site or they redirected the login to a new URL.
If you’re logged in and this happens, your account likely doesn’t have access due to an error, a role change from Admin to something much lower, or rules setup using a permissions plugin.
Ask them to setup a new user for you.
The message “this user doesn’t exist” clearly indicates you’re no longer on the user list. Send them a screenshot with the message you are getting to verify the user list.
They have deleted you and or changed the username.
W
There are several things that could have happened from jealous previous webmaster trying to make you look bad to someone implementing a security feature on the host or, maybe a plugin got activated that redirects logins to a custom URL.
As u/Extension_Anybody150 suggested, contact them to straighten it out ASAP.
Thanks for the help I’ll contact them first thing tomorrow. Its a small operation and no one is particularly tech savvy on the team so hopefully its just a plugin malfunction that is causing a url redirection.
Did someone removed it?