One thing that happened after nightfall on 17 April 1941 was that the 2/48th Battalion brought in a German truck that had been hit by an anti-tank rifle. The truck had a trailer with a new type of anti-tank gun. We would suppose it was a 50mm PAK38 L60 gun. The gun was sent by air to "England", as the Australian historian wrote.
As a result of experience on 17 April, Australian engineers went out to check the minefield in front of the 2/48th Battalion, because they suspected that the Germans might have disabled mines. The effort was stopped by heavy mortar fire. At the wire, they then laid a new mine field and converted some of the existing mines to fire on contact, rather than under control.
Operations by the Ariete Division on 17 April had not gone well. The division was reduced to ten tanks of the one hundred with which they had started the campaign. They had the sort of losses that the 2nd Armoured Division had experienced. Worse yet, the Germans at one point mistook the Italian tanks for British and fired anti-tank guns at them. Rommel made the mistaken identification and ordered the German anti-tank guns to fire on them.
At this point, Rommel was feeling the effects of his extended lines of communication. On 17 April, Rommel had to have his supplies shipped by road from Tripoli. When they could get Benghazi back in operation as a port, they could cut the trip substantially.
Not only the supply situation, but the training and equipment of the Italian units led Rommel to suspend the attacks on Tobruk until he had accumulated greater strength. The current situation was such that he wanted more German forces prior to any further Tobruk attacks. This is based on the account in Vol.III of the Australian Official History.