logging to mmw with GPRSbee rev.7, issue wake/sleep and server response 504

Dear all,

I am trying to run an almost identical sketch “logging_to_mmw.ino” from the modular_sensor examples using a sodaq GPRSbee rev 7. If I am correct the rev.7 uses the same wake functions as the GPRSbee rev 6. So I assumed that I had to define both the sim800 and rev.6 modem in the sketch. See below:

// ==========================================================================
// Wifi/Cellular Modem Main Chip Selection
// ==========================================================================

// Select your modem chip – this determines the exact commands sent to it
#define TINY_GSM_MODEM_SIM800 // Select for a SIMCOM SIM800, SIM900, or variant thereof
#define SIM800_GPRSBEE_R6 // Select with SIM800 for – these use atypical sleep and wake fxns

using these settings most of the system seems to work. I have a signal strength of approximately 40% to 60%, it syncs with NIST and it goes into sleep mode after the initial setup. However, there seems to be an issue with powering up and going into sleep mode during the actual measurement runs. Every even run is successful in doing a measurement on the SIM800. It seems to me that powering on/waking takes just more time than expected (as it just stays on after the first run, and goes down in the second). I attached the entire debugging output (masking tokens with ###). Could anyone guide me in which direction I have to search for a solution.

The second thing that concerns me is the server response if a successful run was finished. The response code is 504, i.e. a gateway timeout, “the server was acting as a gateway or proxy and did not receive a timely response from the upstream server” (according to the wiki https://en.wikipedia.org/wiki/List_of_HTTP_status_codes)
Anyone familiar with this response?

Bernard