From memory (and Who's who in space), Soyuz 10 docked but not hard enough with Salyut 1.
Soyuz 15 returned back after failing with a docking.
Soyuz 18 made an involuntary ballistic flight almost to China.
Soyuz 21: the cosmonauts couldn't stand each other, so they left Salyut 5 early.
Soyuz 23 returned back without docking and splashdowned
Soyuz 25 docking failure
Soyuz 33: engine failure
Soyuz T10: exploqion at launchpad
Soyuz T14: returned home early as the commander felt an end-of-the-world syndrome.
Soyuz TM6: returned 24 hours later than planned, without the orbital module for food and oxygen.
From then on, it worked all the time...

Lots of failures

Raoul