I can not see certain quicksight dashboards, with the result of a permission issue. But my peers can see them perfectly even with lower level, and I could see them weeks before. Those quicksights (below the links) are not shown in the dashboard search either, when I search them, and my peers can.
If your peers can open the dashboards and you cannot, maybe something changed in the permissions you are assigned. I will recommend talking to your QuickSight administrator about this, if all looks good in the permision side, I would recommend filing a case with AWS Support where we can dive into the details so that we can help you further. Here are the steps to open a support case. If your company has someone who manages your AWS account, you might not have direct access to AWS Support and will need to raise an internal ticket to your IT team or whomever manages your AWS account. They should be able to open an AWS Support case on your behalf. Hope this helps!