Why someone cannot get in or cannot edit
Sign-in problems are nearly always the wrong email address. Editing problems are nearly always department scope.
Two different problems that arrive worded the same way. "I cannot get in" is about an invite or an address. "I cannot edit this" is about a department.
A new starter cannot get in
Four causes, in the order they happen.
Nobody sent them the link. Tideswell reserves the seat rather than emailing them, and the confirmation after inviting says to tell them to sign in at your workspace's address with the invited email. Send them that link.
They signed in with the wrong address. The invite is tied to one exact email. Signing in with a personal address instead creates an account with no invite attached, and they land with no workspace.
The invite expired. They last 14 days. Issue a new one.
They were never invited, or the invite was revoked. Check the pending list on Settings › Members, per How to add people and set roles.
Somebody who used to be able to get in cannot
Check whether they were deactivated. A deactivated person loses access immediately and shows greyed out on the roster with a status badge.
Note that the roster has no reactivate button, so this is not something you undo from that screen.
Somebody signs in but sees almost nothing
They are in the workspace and in no departments.
Nearly everything in Tideswell is scoped to a team, so a person with an empty department list has very little to look at. Open their Departments dropdown on the roster and tick the right ones.
Somebody cannot edit a specific record
This is the common one, and the answer is nearly always which department the record belongs to.
Most task, project, milestone and planning permissions are checked against the record's own department. Somebody who leads Marketing is a plain member in Warehouse, and on a Warehouse task they get a member's controls.
Check the record's department first, then that person's standing in that team. Changing a permission row will not fix a scope problem.
Somebody can edit some things and not others on the same record
Because the permissions are separate from one another.
On a task, editing fields, assigning, completing, managing blockers and commenting are five different rights. Somebody can comment on a task they cannot reschedule, and that is working as intended rather than half-broken.
Work out which one is missing using How to work out who can do what in your workspace, then ask for that one.
An admin loosened a permission and it made no difference
Two possibilities.
They needed Settings. The Settings area is gated on being an admin separately, so a permission row never opens a settings screen to a non-admin. See How to set who can do what.
It is a scope problem rather than a rank problem. Setting a row to member does not help somebody who is not in the department at all.
Somebody cannot approve a purchase order
Check whether they raised it or created it. Nobody can approve their own request, and nobody can approve an order they created.
That is a business rule rather than a permission, and an admin cannot override it. Their own requests appear in their queue read-only with the reason on the row.
If they are the only possible approver, that order cannot be approved by anyone and somebody else needs the approve permission. See How to route a purchase order for approval.
Somebody is away and work is stuck behind them
They can hand their standing to a colleague until a date they set, and it expires by itself. See How to hand over your work while you are away.
Set it before going away rather than after.