GL7500 Putty Freezes on HTTP Connect, can't enter anything


I’m using the GL7500 (using a USB connection and Putty) to try an establish an HTTP client connection by following along with the HTTP Commands Example in Section 18.8 of the Airprime HL7588 AT Commands Interface Guide (Rev10). Everything works up until when I send the command “AT+KHTTPHEADER=1”. I get the response “CONNECT”, but then I can’t enter anything into the Putty Console after that (or can’t see that I am entering anything). I have to restart Putty to be able to do anything and then I get a “CME Error: 925” notification. Looking at CME error tables and doing google searches, CME Error 925 doesn’t seem to exist. What am I doing wrong and how do I fix this? See screenshots attached.