Grimsby's winless run was extended to 24 league games after a 1-1 draw at home to Macclesfield.
Jamie Devitt fired the Mariners ahead three minutes before half-time but Richard Butcher equalised for the Silkmen after 58 minutes.
Macclesfield went close through Shaun Brisley and Butcher before Grimsby went ahead.
Jean-Louis Akpro's cross from the left was picked up by Devitt and he cut infield before crashing a left-foot shot into the net.
The equaliser came from a 22-yard free-kick from Butcher, who curled his right-foot shot past Colgan as the goalkeeper lost the flight of the ball.
Akpro should have won it for Grimsby but fired straight at keeper John Brain and then Ricky Sappleton's right foot effort was tipped around the post by Colgan.
Grimsby substitute Nathan Jarman was sent off in the last minute after raising his hands to Silkmen skipper Sean Hessey.
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