Pool heating pump problem

Hi there. I'm new to owning a pool and had a bit of trouble today with my solar heating.

I realised the pool wasn't heating at all today and when I had a look there wasn't any water flowing through the pump. I shut it down and turned back on a couple of times and played around with the lid and lint basket and it eventually primed and started working.

I did clean the basket yesterday and think it might be from that. The process I followed was - while pump off, unscrew lid, lift out basket, clean and return to chamber, place lid back and tighten. It's a Astral E series pump. Should I have filled the chamber with water before putting lid back on? Cheers

Most common problem is a bit of dirt on or around the o ring on the basket lid ir the union on inlet to pump loosened a little