GatewayException: Post Error, error code = 403

I have been having issues launching the Ignition Designer from my laptop over the last few days - Somehow I keep getting the “403 Forbidden” error code from the Gateway and cannot load data from the server which prevents the designer from launching. Occasionally, it won’t even accept my administrator password when it tries to launch the designer, but after trying the same login several times (random number) it will eventually accept it. Once it does, and I select the project I’d like to edit, I get the following error every single time:

com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Post Error, error code = 403
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.getResponse(
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(
at com.inductiveautomation.ignition.designer.gateway.DTGatewayInterface.loadProject(
at com.inductiveautomation.ignition.designer.IgnitionDesigner$StartupProjectDialogHandler$
at Source)

Ignition v7.5.5 (b1255)
Java: Oracle Corporation 1.7.0_21

I have tried everything that I can think of, and nothing works - All Java is up to date, I can configure the server through the web with no issues, I can launch existing projects with no issues, etc. I even deleted all the local cache I know of at /users/me/.ignition and this didn’t help, although I did see it download everything again from the server at next launch. Is there another cache somewhere on my client laptop that I don’t know about?

The other strange thing is that this is isolated to my laptop - We have several other users who have no issues editing projects, etc. Can you help me understand what might be happening? My development ability has been completely stalled since I cannot load the designer at all right now.

It sounds like there might be a permissions issue going on somewhere. Are you able to log in with your username and password from another machine? Have changes been made to the authentication profiles?