IMAP Path Prefix

My email server recently changed settings and ever since I have been getting message saying unable to move mail. I deleted the account and added it manually in order to add the word INBOX to the IMAP Path Prefix in the Advanced Settings for my account, as that solution worked on my other Iphone (after many tries). That whole area of Advanced Settings is grayed out and I am not able to add INBOX. I have added the mail account manually and it still says under everything in Advanced Settings "These settings are installed by the profile ...(my email address)" Help!