Pamac update fails, while pacman succeeds

pacman -Syu seems to work normally. It does not update the multilib.db, so it could be due to that.
pamac update --force-refresh results in the same error.
It seems to be a problem with some gpg keys so I also tried to refresh the keys as mentioned here, which did not resolve the problem

>>> pamac update --force-refresh                                                                                                                     
Preparing...
Synchronisiere Paketdatenbanken...
Aktualisierung von core.db...                                                                                                                           
Aktualisierung von extra.db...                                                                                                                          
Aktualisierung von community.db...                                                                                                                      
Aktualisierung von multilib.db...                                                                                                                       
Aktualisierung von core.files...                                                                                                                        
Aktualisierung von extra.files...                                                                                                                       
Aktualisierung von community.files...                                                                                                                   
Aktualisierung von multilib.files...                                                                                                                    
Fehler: multilib.files: GPGME-Fehler: Keine Daten                                                                                                       
Refreshing AUR...                                                                                                                                       
Resolving dependencies...                                                                                                                               
Checking inter-conflicts...
sudo pacman -Syu                                                                                                                              [1]
:: Synchronizing package databases...
 core is up to date
 extra is up to date
 community                                                        7.6 MiB  12.9 MiB/s 00:01 [#####################################################] 100%
 multilib is up to date
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...