This one is for clients signing in to a portal, and for the team helping them.
Use the portal address your supplier gave you, with the email address they invited. Portal sign-in is separate from an Atwork workspace account — different address, different account.
Use the reset link on the portal sign-in page. A link is sent to your email; follow it and set a new password.
If nothing arrives, check spam first, then confirm you are using the same address the invitation went to.
Work down this list — the first one is right most of the time:
When you invite a client, send the portal link in your own words too — what it is for, and what they will find there. Most "I can't sign in" messages are really "I don't know where to go".
Related: Portal users and access · What is the client portal? · Emails aren't arriving