Hello
I am updating now this, because I had problems with the external micro SD card. I waited to see if the problems disappeared after I changed it. they didn't. However the error now appears less often. I am basically unable to use the Samsung account and all services related to it. I still get the popups.
I checked:
#1.2 Why you may be experiencing problems. I have enough space in the main memory, around 5GB.
#1.3 Wiping the Cache Partition. I wiped the Cache Partition.
#1.5 User Apps: Wiping cache, data and uninstalling.
I did this for most of my personal apps.
Still the same result.
Any ideas?