All I can guess is that you don't play many games with him and feed him any point food so he dosn't have as many Intelligance (pencil icon) /Fasion (star icon) / Social (flower icon) points to get a job! I'll try and find some links to help you.
This is because you do not have enough skill points. What you have to do to get a job is get over 50+ in anyone of the points and then you will get a job in the next 24 hours. Don't worry you will be offered again. To earn skill points play lots and lots of games!
2. The more skill points you have in the skill that that job you are applying for in, the bigger chance of getting accepted you have. For example of I have 283 Social/Kindness, 133 Intelligence and 152 Arts/Talent and I applied for the scientist job, I wouldn't have as much as a good chance as something like a firefighter because the firefighter job is in the Social/Kindness category of jobs and the scientist is in the Intelligence category of jobs, and I have most Social/Kindness and least Ingelligence.
3. Play games if you have really low skill points and just take good care of your Tama!