I have the same issue - not being able to get my attachement to my recipient - and tried to get a log as described: It repeats itself for a long time so I send only a fraction of what appeared in my terminal screen:
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.165: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.166: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.173: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.313: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.315: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.316: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.319: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.321: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.326: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.430: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.430: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.432: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly.
(harbour-whisperfish:33): dconf-CRITICAL **: 12:04:47.433: unable to create file ‘/run/user/100000/dconf/user’: Toegang geweigerd. dconf will not work properly
^[[A^Z[1]+ Stopped /usr/bin/invoker --type=qt5 /usr/bin/harbour-whisperfish
[defaultuser@Xperia10III ~]$ ^C
Good luck, hope this helps …