I would rather you provide you release, to far more people on forums treat *ubuntu 18.04 LTS is the latest as it is the latest LTS release, despite the fact that two releases (18.10 & 19.04) have occurred since then.
The age of your DDWRT router (particularly it’s software) is what I’d use to pick vers= value. DDWRT is a linux box and for my old ddwrt thing it still runs linux kernel 2.6 so vers=1.0 maybe required (on more modern boxes like my Lubuntu workstation), but your DDWRT could be newer than mine (key date is before OR after wannacry as it caused the most change with SaMBa since creation in 1983 in my opinion).
As for case - the most important thing is the
mkdir command that created the directory, but nothing in your post provides that detail (if created earlier, a
stat etc. of it wasn’t included), thus there is no proof of it’s existence in your provided detail outside of your “does exist” explanation; why I suggested checking…
It could also be you have need to provide a
,password= value for mounting to occur which caused your rejection.
smbclient doesn’t need any password as protocol doesn’t require it, but the
mount will access data so will require it if the DDWRT client has been setup with username/password combination.