remmina can not save password
make sure you own the .remmina folder (and all its contents).
$ ls -l --directory ~/.remmina/
Your user name should appear on the ls record like:
drwx------ 2 username username 4096 Jan 1 12:15 /home/username/.remmina
If root owns this file, You can correct the permissions like:
# chown --reference ~/ --recursive ~/.remmina/