phone stops synching mails, calendar, stops receiving sms, etc

[Eliminateur]

i'm having a serious issue with my new WP in which after random numbers of days all the sudden it stops synching email, stops receiving SMS, synch calendar, etc, essentially ANYTHING that has to do with the "accounts" stops working.
for example: you go to email, manual sync... nothing
you go to calendar, try to display a previously hidden calendar... nothing is shown(even when you see the checkbox).

If i go to "email+accounts" it does nothing, loads for some seconds and goes back to settings, same if i press "add account" on either calendar/apps.

It's quite annoying and VERY serious as i have practically NO WAY of knowing this fails until i notice a mismatch between my web inbox and the phone(usually phone gets mail faster than gmail inbox) and the ONLY way to fix it is a power cycle(plane mode does nothing) and then a deluge of SMS starts pouring in.
whatsapp does keep working, same with normal in/out calls

?is there an urgent patch/fix for this i can apply?.

phone started as 8.1 clean so no baggage from upgrades

 

[the-wrangler]

Check the date and time - I rebooted once and found the date and time changed, then wouldn't sync. Also password, or cell/wifi reception?

I also recall there used to be this problem which I did have too. I had to turn off text message back up, then it would sync. I believe I turned off all the back up (text, phone/apps), deleted my previous phone backups, synced everything then turned on backups again. This fixed my issue. Hope that helps you out, and if not I'm sure someone else may have a trick to help you

 

[Eliminateur]

no date and time change after a powercycle.
cell wifi reception is good, and even if it wheren't at some point i moved all over the place with good signal.

for now i've disabled SMS backup, i'll wait and see

 

[MartLea]

My Nokia Lumia 620 CV UK, Cyan 8.1.1.1 Dev Preview latest versions has decided to stop automatically syncing to my linked email accounts. Manual sync still works fine but no matter what period I set automatic sync to 1hr, 30mins etc. it no longer works.
Date and time are both correct. Due to backup still not working I am reluctant to hard reset the phone. Soft reset makes no difference. Phone is always connected to WiFi and has plenty of memory & storage free.