Ab dem 21. Januar 1944 unternahm die Luftwaffe eine erneute Luftoffensive unter der Bezeichnung Unternehmen Steinbock. Diese wurde nach hohen Verlusten der Luftwaffe am 29. Mai 1944 abgebrochen, und von den Briten im Nachhinein als "Baby Blitz" bezeichnet. (Operation Steinbock may also have been known in Britain 'Operation Capricorn', AOB).
Further briefly: Owing to high losses the Germans abandoned operation Steinbock, in Britain known as Baby-Blitz.
Brief translation and interpretation:
During the night of 21 to 22 January 1944 (the German) operation Steinbock begun. Planned was for 447 aircraft in two waves with interruptions of 6 hours attacking London. In total only about 32 tons of bombs had been dropped. Only half of it reached British soil. The main ground for this was: daß die Luftwaffe aufgrund eines nicht fehlerfreien Funknavigationsverfahrens die Angriffsziele nicht sicher fand. Außerdem waren die Pfadfinder der I/KG 66 zu schwach besetzt.
Briefly: misfortune was due to failing radio navigational aids! Nicht fehlerfrei means, in my perception, not functioning well.
Please read the Wikipedia content yourself
Although, there might have been more than a single reason to fail. Was the Freya-EGON system powerful enough to guide over longer range?
Were the operators trained well?
Was the time-base reference in the aircraft coping with environment?
Did they encounter friendly interference?
Let us also notice what Wikipedia UK has to say on this event:
The first attack on London was mounted on the night of 21/22 January. Codenamed Unternehmen Mars, sections of the British capital were given codenames after devastated German cities — Berlin, Hamburg, Hannover, to emphasize the retaliatory nature of the operation for the air crews.The first raid targeted the area designated as 'München'—the Waterloo area of London. The attack consisted of two waves with 447 bomber sorties, primarily Ju-88s and Do-217s, carrying 475 tons of bombs, with 60 per cent of the payload incendiaries. The first wave bombed from 2040 hours until 2209 and the second wave 0419 to 0545.Many bomber crews flew double sorties on this night.
Despite the extensive use of 'duppel' ( the Luftwaffe equivalent of the RAF's window anti-radar device) and target marking with white and green flares by KG 66, the Luftwaffe's pathfinders, hardly any bombers reached London and only some 30 tons were estimated to have fallen on the capital, with bombs and incendiaries scattered throughout the Home Counties.The Houses of Parliament, Parliament Square, Westminster Hall, the Embankment, New Scotland Yard and parts of Pimlico were all hit by incendiaries. Some 14 people were killed and 74 injured.
Hitler was reportedly outraged that the Luftwaffe failed to find London though it was only 150–200 km (93–120 mi) from German ground control stations while the British were hitting German towns, not just city targets, from 1,000 km (620 mi) away in bad weather. Peltz responded that the failures owed as much to the Luftwaffe's lack of interference-free radio and navigational aids* as to untrained crews, and that the British with their H2S and Gee systems were technologically ahead of the Germans. The lack of dedicated pathfinder units also caused navigational problems, as the few aircraft employed in this role were more at risk from electronic counter-measures and fighter interception. The heavy British defences forced the Luftwaffe to fly meandering 'dog-leg' courses and inexperienced German crews quickly got lost. Reconnaissance flights over England had also stopped, which prevented the Luftwaffe from gathering intelligence on British radar and radio frequency bands.
* Modified text under score by AOB
Approximately 40 bombers were lost to all causes. Luftwaffe records indicate 25 aircraft fell to enemy action, RAF Mosquitos claimed 16 bombers destroyed or probably destroyed, and the other 9 probably fell to anti-aircraft fire. Just as worrying for the Luftwaffe was a further 18 bombers were lost to non-combat causes, including pilot error, navigation error leading to running out of fuel or landing crashes at base.
The first operation coincided with the Allied landings at Anzio in Italy, and immediately three of the Kampfgruppen were returned to Italy. Bad weather also intervened, and the next raid on London was delayed until 28 January, with only Me 410 fast bombers and Fw 190 fighter-bombers taking part. On the following night a 285-strong bomber force, of mostly Ju-188s and Ju-88s attacked, and started a major fire in the Surrey Commercial Docks.
The bomber force lost 28 aircraft shot down. Following this operation I./KG 40 was withdrawn.
The two January attacks on London caused the death of about 100 people, with some 200 injured.
240 sorties were flown on 3/4 February, with only 26 tons of bombs falling on London and scattered bombing across South east England. Fires were started in Hackney and Tilbury with 17 killed and 12 injured in the capital.
On 13/14 February 161 tonnes were dropped over England, with 4 tons on the capital.
A series of far more accurate raids now ensued, as on the 18/19th, with 200 sorties dropping 185 tons of bombs on Whitehall, Queen's Gate and in Pimlico in a short sharp 30 minute raid. Civilian casualties were 180 killed and 463 seriously injured.
On 20/21 February some 200 aircraft were committed, with I./KG 100 contributing 14 He 177s. Whitehall was hit again as was Horse Guards Parade, St. James's Park, the Treasury, the Admiralty, the War Office and the Scottish Office. Windows were also blown out in 10 Downing Street. 216 were killed on the ground and 417 badly injured. On the night of the 23rd 32 London boroughs recorded incidents, with 72 people killed in Chelsea following a direct hit on a block of flats near the King's Road. In total there were 160 fatalities and 348 serious injuries that night. Targets on the night of February 24 were government buildings around the Westminster area, with over 170 aircraft targeting London.
The 1,300 operational sorties carried out in February had produced mixed results. However, bomber losses for the month, at 72 aircraft, remained prohibitively high.
In March there were four attacks on London, followed by raids on Hull and Bristol. On 14/15 March, 100 German aircraft dropped incendiaries and high explosives across Westminster, Hyde Park, Knightsbridge, Rochester Row, Monck Street, Cliveden Place and two churches in Medway Street and Flask Lane were hit, set alight or damaged. On 21 March Paddington Railway Station was also hit.
Attacks on the capital continued until the night of 20/21 April 1944. By this time 31 major raids had been flown since January, 14 against the British capital. Peltz's force had dropped a total of some 2,000 tons of bombs at a cost of 329 bombers lost.
From late April German attacks switched to the channel ports on the south coast of England, where shipping for the forthcoming Allied invasion of Europe was massing. However, the offensive yielded little tangible results for the Luftwaffe, at a high cost in aircrew and aircraft.