There is a bug in Foundry 0.8.7 and 0.8.8 where the core migration might not have happened, which causes the passwords to fail and the “reset password” to not do anything. The only fix for now is to export your world (from The Forge) then edit the world.json file inside the world with a text editor and changing the line :
"coreVersion": "0.8.8",
into :
"coreVersion": "0.8.6",
Then import the world again. Hopefully this time the migration to 0.8.8 succeeds and you can access your world.
The issue has been reported to the Foundry team and we expect it to be fixed for 0.8.9. You can follow the issue here
I hope that helps!