Hi ​@Jorma Wagner  — thanks for describing the issue clearly. Since the guest user can open other boards they’ve been invited to but sees only a blank screen on this one specific board, here are the most likely causes and next steps:

Board Content Exists Outside Viewport

Sometimes, especially after duplications or edits, content is placed far off the canvas — so the board opens, but appears blank. Ask the guest to try zooming out manually and dragging around the canvas

Board Permissions Not Set Properly

Even though the guest has access to some boards, this one may not have the right board-level permissions (e.g., it might only be shared with team members, not guests).

• Go to the board > click "Share"

• Under “Who has access”, make sure your guest is listed specifically by email or the board is shared with “Anyone with the link can view/edit”

• If the guest was added only via a Microsoft invite, try re-inviting them directly by email

Board Is Empty or Content Accidentally Deleted

Check if the board actually contains any frames or objects, and whether they may have been removed or placed outside visible bounds.

Try the following:

• Opening the Frames panel (left-side toolbar > Frames) to check if any content is listed

• If there’s no content at all, it might’ve been cleared or never saved

Cached or Incomplete Load

Sometimes the board looks blank due to browser issues. Ask your colleague to try in:

• A private/incognito window

• A different browser (e.g. Firefox or Chrome)

• After clearing browser cache

If none of these work, please share:

• Whether the colleague can access other boards in the same team

• A screenshot of what they see

• How the board is currently shared (e.g. team-only, public link, etc.)

We’ll help you sort it out!

Hi Eca, thx for for immediate reaction and response! I’ve tried all of your proposals (some of them already in advance to your message). Now it works, but it remains strange, because my colleague could open the board only with Chrome. Firefox, Bing and Safari responds only with error messages… Must be a problem on her side… 
 

Regards and all the best