Dax formula not working after merging and appending

[Hamdan1234]

Hello,

I have table of courses that people take . Each course has life like it is for 36 months , and 24 months etc. I got a DAX formula given below which on the basis of course taken shows whether the person again need to do the course or is he/she is updated. I merged two tables of online and classroom courses and it was working. The formula is:

ValidUntillll =

VAR _0 = ADDCOLUMNS('Classroom Training',"ValidTill", 'Classroom Training'[Class End Date]+(CONVERT(LEFT('Classroom Training'[Training Matrix.Recurrence],2),INTEGER)*DIVIDE(365,12)))

RETURN

MAXX(_0,[ValidTill])

This was working fine then I appended and merged few more tables now the formulas is not giving any error but when I put it in the table I get the below error. 

The formula is:

ValidUntillll =

VAR _0 = ADDCOLUMNS('Classroom Training',"ValidTill", 'Classroom Training'[Class End Date]+(CONVERT(LEFT('Classroom Training'[Training Matrix.Recurrence],2),INTEGER)*DIVIDE(365,12)))

RETURN

MAXX(_0,[ValidTill])

The error is above one. Is their anything wrong that I am doing? Please improve my formula and get the right formula. 

[v-xiaotang]

Hi @Hamdan1234 

Is there any exception in your data? It seems that there are some text that cannot be converted to integers.

For example,

the measure is OK, but once I put it into visual, the same prompt will appear.

Best Regards,

Community Support Team _Tang

If this post helps, please consider Accept it as the solution to help the other members find it more quickly.

[AlexisOlson · Accepted solution]

From the error, I would guess that you have a row in the column Classroom Training'[Training Matrix.Recurrence] that start with "on".

[Hamdan1234]

Yes I saw and found out there was a value of "once" in the column