The default htaccess rules usually redirect the /admin/ to /wp-admin/ nicely and sometimes serves as a good warning if the site is running Windows, Nginx, or misconfigured which is good for me to know which is why I use /admin/ first on a site just to have a quick look.
Yeah, I tried it there and it worked!
I didn’t mention dumping cache because I figured if the OP can’t login from my link then he probably can’t dump the cache… gotta get there first. And if it doesn’t work he’ll come back and tell me.
And, if he has a cache then I’m hoping he has something that handles the cache-control headers to dump the cache for him automatically. Most of the cache plugins, KeyCDN’s cache enabler, and AutoOptimize all help make that magic happen.
Most of what I do here is done on purpose and I’m glad to explain that just in case I’m on the wrong track somewhere or missed something. There’s always something!!! <GRIN>