User receives the message "Failed to login to Salesforce.com An error has occurred while trying to contact salesforce"  when trying to record an email to salesforce.  Username and password are correct and they can log in to salesforce.  Any ideas

Does anyone know how to remove a line break from a field?
I am trying to use MailingAddress in a hyperlink formula but it breaks every time there is a contact with a two line mailing address.

I have tried the following and they did not work:
substitute(MailingAddress,BR(),"")
substitute(MailingAddress,"\n","")
substitute(MailingAddress,\n,"")
trim(MailingAddress)

For reference my formula looks something like this:
hyperlink("http://linklocation.com?address="&MailingAddress,"Link Text", "_blank")