Godaddy forward with masking not working

Hi all,

I am not able to forward my godaddy-managed domain to my octoprint server with masking turned on (masking makes my password manager happy and it looks better on the URL line: http://domain:5002/?#temp)

I AM able to access my instance by, but does not work IF masking is turned on (works fine if masking is set to permanent (301) )

I contacted godaddy and they are telling me that it is a server issue and it is preventing masking (not completely sure I buy this, but they have been generally correct in the past)

Not sure which logs to look at

FWIW, this is running on a raspberry pi

Thanks for any help you can provide