@martin - thanks. It's not git itself I have problems with, but actually your article reminded me that I had not set the globals for my user and email, so very useful indeed!
![Smiley :)](https://www.os2world.com/forum/Smileys/default/smiley.gif)
@Dave - rebooting did not help, I got the same error. However, I tried using HTTPS rather than SSH (I've always used SSH before so it had not occurred to me to use an alternative method). And bingo!
It means manually entering the password (well it can be cached in the globals I guess so not too bad), but all seems working. I have cloned, added, committed and pushed, and my changes have appeared on gitlab.
Thanks both for all for your suggestions. The OS/2 community on these forums is really wonderfully helpful .